Heat supply device of absorption heat pump unit
By designing an evaporator using wear-resistant and corrosion-resistant materials and setting up interfaces for scale inhibitors and scale removal, the problems of low temperature and scaling risk of desulfurization slurry were solved, achieving efficient heat recovery of desulfurization slurry and increasing heating temperature to meet heating needs.
Patent Information
- Application Number
- CN202520265406.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-19
- Publication Date
- 2026-01-27
- Estimated Expiration
- 2035-02-19
AI Technical Summary
The temperature of the desulfurization slurry is lower than that of the heating return water, making it difficult to utilize the heat. Furthermore, the high solids content, corrosiveness, and scaling risk of the slurry increase the wear and corrosion of the heat exchange surface, making it difficult to effectively utilize its heat.
The evaporator uses wear-resistant and corrosion-resistant materials, and is equipped with scale inhibitor addition and scale removal interfaces. Combined with a smooth inner wall design, it utilizes a lithium bromide absorption heat pump unit to drive heat recovery and raise the heating temperature through a steam heater.
By effectively utilizing the low-temperature heat of the desulfurization slurry, the heating temperature can be increased to 80℃ to meet heating needs, extend equipment life, reduce maintenance costs, and ensure stable heat exchange efficiency.
Smart Images
Figure CN223840460U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to an absorption heat pump unit, and more particularly to a heating device for an absorption heat pump unit that directly uses flue gas desulfurization slurry as a low-temperature heat source. Background Technology
[0002] Limestone-gypsum flue gas desulfurization (FGD) is a widely used method in power plants. It utilizes a 10-15% limestone slurry to absorb sulfur oxides from the flue gas and further oxidize them into calcium sulfate. The normal temperature range of the desulfurization slurry is typically 40-50℃. During the desulfurization process, the slurry absorbs heat from the flue gas, and since limestone-gypsum FGD is an exothermic reaction, the slurry temperature gradually increases, requiring the release of some heat.
[0003] However, since the temperature of the desulfurization slurry is only slightly higher than the temperature of the heating return water, and considering the temperature difference in heat exchange, the heat from the desulfurization slurry is difficult to directly exchange for heating. In particular, power plants are often far from the heating terminals, and the temperature of the heating network supply water is high, much higher than the temperature of the desulfurization slurry, and even the temperature of the heating network return water is higher than that of the desulfurization slurry, which generally makes it impossible to utilize the heat from the desulfurization slurry.
[0004] Meanwhile, the high solids content in the flue gas desulfurization slurry makes it highly abrasive; the solids easily precipitate, and the chemical reactions during the desulfurization process easily produce calcium sulfate crystals, all of which increase the risk of scaling on the heat exchange surface; furthermore, the high electrolyte concentration in the flue gas desulfurization slurry, especially acidic substances such as chloride ions and sulfur oxides, is highly corrosive. Therefore, abrasion, corrosion, and scaling make it difficult to effectively utilize the heat of the desulfurization slurry. Utility Model Content
[0005] The purpose of this invention is to overcome the above-mentioned shortcomings of the prior art and provide an absorption heat pump unit heating device that is highly corrosion resistant, wear resistant, and not prone to scaling. It can utilize the low-grade waste heat of desulfurization slurry and power plant steam to efficiently produce medium-temperature or high-temperature hot water for heating and other purposes, thus meeting different needs.
[0006] The technical solution of this utility model is: an absorption heat pump unit heating device, including a unit body; the liquid inlet of the evaporator of the unit body is connected to the liquid inlet pipe for inputting desulfurization slurry; the liquid outlet of the evaporator is connected to the liquid outlet pipe for outputting desulfurization slurry after heat exchange; the liquid inlet pipe is provided with a scale inhibitor addition interface; both the liquid inlet pipe and the liquid outlet pipe are provided with scale removal interfaces.
[0007] Furthermore, the hot water outlet of the condenser of the unit body is connected to the inlet of the steam heater, and the high-temperature outlet of the steam heater is connected to the hot water supply end via a pipeline.
[0008] Furthermore, the liquid inlet of the evaporator is connected to the desulfurization slurry outlet of the desulfurization unit through a liquid inlet pipe, which is used to introduce the desulfurization slurry into the heat exchange tube of the evaporator and transfer its heat to the heat network return water.
[0009] Furthermore, the liquid inlet pipe is provided with a scale removal inlet, and the liquid outlet pipe is provided with a scale removal outlet, so that the cleaning medium entering the scale removal inlet can enter the heat exchange tube of the evaporator and be discharged through the scale removal outlet.
[0010] Furthermore, the scale removal inlet and outlet are connected to a rubber ball cleaning system or a cleaning agent system; when connected to a rubber ball cleaning system, a ball-collecting net for rubber ball recovery is provided at the scale removal outlet.
[0011] Furthermore, the scale removal port is located near the evaporator, while the scale inhibitor addition port is located away from the evaporator.
[0012] Furthermore, valves are provided at the scale inhibitor addition interface and / or scale removal interface; valves are also provided on the liquid inlet pipe and liquid outlet pipe.
[0013] Furthermore, the inner wall of the heat exchange tube of the evaporator is a smooth surface, while the outer wall of the heat exchange tube is a rough surface.
[0014] Furthermore, the heat exchange tubes of the evaporator are made of a highly wear-resistant material; the water chamber of the evaporator is made of a composite material of a highly wear-resistant and highly corrosion-resistant material and low-carbon or low-alloy steel.
[0015] Furthermore, the unit body is a steam-type lithium bromide absorption heat pump unit, with steam as the driving heat source entering the generator tube bundle of the unit body, and flue gas desulfurization slurry as the low-temperature heat source entering the evaporator tube bundle of the unit body; the absorber inlet of the unit body is connected to the heating return water end through a pipeline, and the absorber outlet is connected to the condenser inlet.
[0016] The beneficial effects of this utility model are:
[0017] (1) By setting up an antiscalant addition interface on the liquid inlet pipe, the problems of fouling and scaling of desulfurization slurry in heat exchange tubes can be further reduced, effectively reducing maintenance and extending service life, and can be operated for a long time;
[0018] (2) By setting up scale removal interfaces on the liquid outlet pipe and liquid inlet pipe, a convenient cleaning channel is provided, which can remove scale in the heat exchange tube by physical or chemical methods when necessary, and ensure long-term stable heat exchange efficiency.
[0019] (3) High wear-resistant and corrosion-resistant materials are used as heat exchangers for power plant flue gas desulfurization slurry to extract heat and make it durable;
[0020] (4) Use heat exchange tubes with smooth surfaces to reduce problems such as fouling and scaling of desulfurization slurry in the heat exchange tubes and ensure heat exchange efficiency;
[0021] (5) Give full play to the function of lithium bromide absorption heat pump unit in utilizing low-temperature waste heat. Use desulfurization slurry as a low-temperature heat source and power plant steam as a high-temperature heat source to drive lithium bromide absorption heat pump, recover the heat in the desulfurization slurry in advance, thereby raising the heating temperature to about 80°C, efficiently producing medium-temperature hot water for heating and other purposes, meeting the normal heating network water supply temperature requirements; and heat the medium-temperature hot water into high-temperature hot water through steam heater, which can meet the long-distance high-temperature heating demand. Attached Figure Description
[0022] Figure 1 This is a structural schematic diagram of an embodiment of the present utility model.
[0023] Explanation of reference numerals in the attached diagram:
[0024] 1. Unit body; 2. Steam heater; 3. Liquid inlet pipe; 4. Liquid outlet pipe; 5. Valves; 6. Ball catcher net. Detailed Implementation
[0025] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.
[0026] like Figure 1 As shown: An absorption heat pump unit heating device includes a unit body 1 and a steam heater 2. The liquid inlet of the evaporator of the unit body 1 is connected to the liquid inlet pipe 3 for inputting desulfurization slurry; the liquid outlet of the evaporator is connected to the liquid outlet pipe 4 for outputting the desulfurization slurry after heat exchange; the liquid inlet pipe 4 is provided with a scale inhibitor addition interface; both the liquid inlet pipe 3 and the liquid outlet pipe 4 are provided with scale removal interfaces.
[0027] Specifically, the unit body 1 is preferably a steam-type lithium bromide absorption heat pump unit, mainly comprising a generator, condenser, absorber, evaporator, and heat exchanger. The lithium bromide absorption heat pump unit uses power plant steam as the driving heat source, which enters the generator tube bundle of the unit body 1, and uses the power plant flue gas desulfurization slurry as a low-temperature heat source, which enters the evaporator tube bundle of the unit body 1. The heat return water is heated through the absorber and condenser of the unit body 1 to meet the heating requirements. Since the low-temperature heat source temperature range of the lithium bromide absorption heat pump unit is 20-65℃, it precisely covers the normal temperature range of the flue gas desulfurization slurry (40-60℃). Therefore, the heat of the flue gas desulfurization slurry can be rationally utilized according to the requirements of the desulfurization process. It is understood that the lithium bromide absorption heat pump unit is a standardized piece of equipment, and its working principle will not be described in detail here.
[0028] In this embodiment, the hot water outlet of the condenser is connected to the inlet of the steam heater 2. The high-temperature outlet of the steam heater 2 is connected to the hot water supply end via a pipeline, and the steam inlet of the steam heater 2 is connected to the power plant steam system or other steam sources via a pipeline. The generated condensate is discharged through the condensate outlet. Since the lithium bromide absorption heat pump unit can heat the 40°C return water of the heating network to about 60-80°C, it can only meet general heating requirements. To meet the demand for higher temperatures, this embodiment adds a steam heater 2 at the rear of the unit body, using steam to heat the medium-temperature hot water into high-temperature hot water (reaching near steam temperature) to meet different requirements. The steam heater 2 can be a plate heat exchanger, a shell-and-tube heat exchanger, or a wound tube heat exchanger, etc. The steam condensate is returned to the boiler, or when the steam condensate does not need to return to the boiler, steam is directly introduced into the medium-temperature water for heating.
[0029] In this embodiment, the evaporator's inlet is connected to the desulfurization slurry outlet of the desulfurization unit via inlet pipe 3, and the evaporator's outlet is connected to the desulfurization slurry inlet of the desulfurization unit via outlet pipe 4. The desulfurization slurry enters the heat exchange tubes of the evaporator via inlet pipe 3, where it exchanges heat with the low-temperature medium (such as water vapor) inside the evaporator. After absorbing heat, its temperature rises. The desulfurization slurry, after heat exchange, returns to the desulfurization unit via outlet pipe 4 for flue gas desulfurization. The water vapor in the evaporator releases heat and enters the absorber, where it exchanges heat with the lithium bromide solution. The absorber's inlet is connected to the heating return water supply via a pipe, and the absorber's outlet is connected to the condenser's inlet. The heating return water enters the absorber's heat exchange tubes, heats up, and then enters the condenser's heat exchange tubes. After further heating, it is output from the condenser's hot water outlet to the steam heater to obtain hot water at a higher temperature.
[0030] In this embodiment, a scale inhibitor addition port is provided on the liquid inlet pipe 3, preferably located near the liquid inlet of the liquid inlet pipe. Due to the high solids content (including calcium ions and sulfate ions) of the desulfurization slurry, calcium sulfate scale is easily formed, affecting the heat exchange capacity of the unit. This scaling is even more severe in the desulfurization unit, potentially impacting its operation. Therefore, a scale inhibitor addition port is provided on the liquid inlet pipe. By adding scale inhibitors such as organophosphates, the scale inhibitor input from the addition port can sequentially enter the heat exchange tubes and outlet pipe of the evaporator through the liquid inlet pipe, and then enter the desulfurization unit through the outlet pipe. This prevents scaling of the desulfurization slurry, thereby preventing and mitigating scale formation in the heat exchange tubes during operation, ensuring heat exchange efficiency. Furthermore, adding scale inhibitors also helps prevent scaling throughout the entire desulfurization unit. It is understood that a valve can be pre-installed at the scale inhibitor addition port.
[0031] In this embodiment, scale removal interfaces are also provided on the liquid outlet pipe 4 and the liquid inlet pipe 3. The scale removal interfaces are located in front of the scale inhibitor addition interface, i.e., near the evaporator. Since desulfurization slurry can cause scaling, if the aforementioned scale inhibitor is added incorrectly or scale accumulates after long-term operation, this embodiment adds scale removal interfaces to solve this problem. For example, a scale removal outlet is provided on the liquid outlet pipe, and a scale removal inlet is provided on the liquid inlet pipe. Valves 5 can be reserved on both interfaces. The scale removal inlet is connected to the outlet of the ball cleaning system or other cleaning systems via a pipe, and the scale removal outlet is connected to the inlet of the ball cleaning system or other cleaning systems via a pipe. If a ball cleaning system is connected, a ball collection net 6 for ball recovery is also provided at the scale removal outlet position of the liquid outlet pipe 4. When using a cleaning agent, cleaning is performed during unit downtime after scaling occurs. For example, calcium sulfate cleaning agent is added, and a cleaning pump is connected. The cleaning agent enters the inlet pipe 3 through the scale removal inlet to chemically remove scale and other deposits generated inside the heat exchange tubes of the evaporator, restoring heat exchange efficiency. The cleaning agent is then discharged through the scale removal outlet pipe 4. When a cleaning agent is not used, but instead a rubber ball cleaning system is connected, the unit can be shut down, and scale and other deposits generated inside the heat exchange tubes can be physically removed to ensure heat exchange efficiency. The cleaned rubber balls are then recovered through the ball collection net 6.
[0032] In this embodiment, valves 5 are also provided on the outlet pipe 4 and the inlet pipe 3 between the scale removal interface and the desulfurization device, which can be used to adjust the flow rate of various liquids passing through the two pipes.
[0033] In this embodiment, the high solids content in the flue gas desulfurization slurry results in strong abrasiveness; simultaneously, the high concentration of electrolytes in the slurry, especially acidic substances such as chloride ions and sulfur oxides, is highly corrosive. When the flue gas desulfurization slurry is introduced into the evaporator heat exchange tubes, these factors will affect the heat exchange tubes of the unit's evaporator. Therefore, the heat exchange tube material is preferably a highly wear-resistant material, including but not limited to high-strength, high-hardness materials such as titanium alloys, 2507 duplex stainless steel, and 2205 duplex stainless steel.
[0034] In this embodiment, due to the abrasiveness and strong corrosiveness of the flue gas desulfurization slurry, the automatic cleaning system for the rubber balls needs to be made of the same wear-resistant and corrosion-resistant material as the heat exchange tubes.
[0035] In this embodiment, the evaporator water chamber of the unit body 1 is made of a composite material of high wear-resistant and high corrosion-resistant materials and low-carbon or low-alloy steel. The side of the composite material that contacts the desulfurization slurry is preferably made of titanium alloy, 2507 duplex stainless steel, or 2205 duplex stainless steel. The side of the composite material that does not contact the desulfurization slurry is preferably made of Q235 steel, No. 20 steel, Q345 steel, or Q345R steel. The composite material is designed as two layers, welded together to form a single unit.
[0036] In this embodiment, since the evaporator heat exchange tubes pass through the flue gas desulfurization slurry, the inner wall of the heat exchange tubes is designed to be smooth to reduce the impact of solid matter sedimentation and calcium sulfate crystallization in the slurry on heat exchange. The outer wall of the heat exchange tubes is roughened by sandblasting or shot blasting to facilitate the rapid diffusion and evaporation of water droplets on its surface. The outer wall of the heat exchange tubes can also be enhanced by other methods such as fins and patterns, but it should be ensured that the inner wall of the heat exchange tubes is smooth.
[0037] In summary, this embodiment, on the one hand, fully utilizes the low-temperature waste heat utilization capability of the lithium bromide absorption heat pump unit, using desulfurization slurry as a low-temperature heat source and power plant steam as a high-temperature heat source to drive the lithium bromide absorption heat pump. This allows for the early recovery of heat from the desulfurization slurry, thereby raising the heating temperature to approximately 80°C. This efficiently produces medium-temperature hot water for heating and other applications, meeting the normal water supply temperature requirements of the heating network. Furthermore, the medium-temperature hot water is heated to high-temperature hot water by a steam heater, meeting the needs of long-distance high-temperature heating. On the other hand, by installing a scale inhibitor addition interface on the inlet pipe, scale accumulation and fouling in the heat exchange tubes of the desulfurization slurry are effectively prevented, maintaining the efficient operation of the heat exchange system. Scale removal interfaces on the outlet and inlet pipes provide convenient cleaning channels, enabling the removal of scale from the heat exchange tubes by physical or chemical methods when necessary, ensuring long-term stable heat exchange efficiency. In conclusion, these measures effectively extend the unit's service life, reduce maintenance costs, and guarantee the continuous and efficient operation of the heat exchange system.
[0038] In other words, this embodiment can utilize the waste heat of flue gas desulfurization slurry from thermal power plants with a solid content of up to 10% or more, overcoming its high corrosivity, high abrasiveness and easy scaling risks, and ultimately obtaining hot water for heating and other purposes.
[0039] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.
Claims
1. A heating device for an absorption heat pump unit, comprising a unit body; characterized in that, The inlet of the evaporator of the unit body is connected to the inlet pipe for inputting desulfurization slurry; the outlet of the evaporator is connected to the outlet pipe for outputting desulfurization slurry after heat exchange; the inlet pipe is provided with a scale inhibitor addition interface; both the inlet pipe and the outlet pipe are provided with scale removal interfaces.
2. The absorption heat pump unit heating device according to claim 1, characterized in that, The hot water outlet of the condenser of the unit body is connected to the inlet of the steam heater, and the high-temperature outlet of the steam heater is connected to the hot water supply end via a pipeline.
3. The absorption heat pump unit heating device according to claim 1 or 2, characterized in that, The liquid inlet of the evaporator is connected to the desulfurization slurry outlet of the desulfurization unit through a liquid inlet pipe, which is used to introduce the desulfurization slurry into the heat exchange tube of the evaporator and transfer its heat to the heat network return water.
4. The absorption heat pump unit heating device according to claim 1 or 2, characterized in that, The liquid inlet pipe is provided with a scale removal inlet, and the liquid outlet pipe is provided with a scale removal outlet, so that the cleaning medium entering the scale removal inlet can enter the heat exchange tube of the evaporator and be discharged through the scale removal outlet.
5. The absorption heat pump unit heating device according to claim 4, characterized in that, The scale removal inlet and outlet are connected to a rubber ball cleaning system or a cleaning agent system; when connected to a rubber ball cleaning system, a ball-collecting net is provided at the scale removal outlet for rubber ball recovery.
6. The absorption heat pump unit heating device according to claim 1 or 2, characterized in that, The scale removal port is located near the evaporator, and the scale inhibitor addition port is located away from the evaporator.
7. The absorption heat pump unit heating device according to claim 1 or 2, characterized in that, Valves are provided at the scale inhibitor addition interface and / or scale removal interface; valves are also provided on the liquid inlet pipe and liquid outlet pipe.
8. The absorption heat pump unit heating device according to claim 1 or 2, characterized in that, The inner wall of the heat exchange tube in the evaporator is smooth, while the outer wall is rough.
9. The absorption heat pump unit heating device according to claim 1 or 2, characterized in that, The unit body is a steam-type lithium bromide absorption heat pump unit. Steam is used as the driving heat source and enters the generator tube bundle of the unit body. Flue gas desulfurization slurry is used as a low-temperature heat source and enters the evaporator tube bundle of the unit body. The absorber inlet of the unit body is connected to the heating return water end through a pipeline, and the absorber outlet is connected to the condenser inlet.