A heat tracing system utilizing desulfurization system flue gas waste heat
By utilizing the waste heat of flue gas in the boiler desulfurization system to heat the flue and urea solution tank, and achieving multi-pipe heat exchange through return water branch pipes, the problem of unused waste heat of the original flue gas in the boiler is solved, realizing multiple utilization of waste heat and cost reduction.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- TIANJIN GUOHUA PANSHAN POWER
- Filing Date
- 2025-06-13
- Publication Date
- 2026-05-29
AI Technical Summary
The waste heat from the original flue gas in existing boilers is not fully utilized, resulting in heat loss. Furthermore, existing heat tracing methods, such as electric heat tracing and steam heat tracing, are either costly or have poor safety, and there is a lack of effective waste heat utilization solutions.
Design a heat tracing system that utilizes the waste heat of the original flue gas in the desulfurization system. By wrapping heat exchange coils around the outer walls of the flue and urea solution tank, the high-temperature waste heat of the flue gas is used to heat the outdoor pipes and urea solution. Heat exchange between various pipes is achieved through return water branch pipes. Safety monitoring is carried out in conjunction with an expansion tank and thermometers.
This approach enables multiple uses of waste heat from flue gas, reducing energy consumption and costs, improving production efficiency, and enhancing safety and applicability.
Smart Images
Figure CN224302332U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the technical field of flue gas waste heat recovery, specifically a heat tracing system that utilizes the waste heat of the original flue gas from a desulfurization system. Background Technology
[0002] Currently, the temperature of raw flue gas from boilers in domestic thermal power plants, steel mills, and chemical plants before entering the desulfurization system is mostly between 125 and 140°C, with a large amount of residual heat remaining unused, resulting in significant heat loss. Currently, these companies use either electric or steam tracing for winter freeze protection of outdoor pipelines and for heat tracing of denitrification urea solutions. Electric tracing requires a power supply and heating tape, and the heating tape has a limited lifespan of approximately five years, requiring replacement. Electric tracing also incurs high operating costs. Steam tracing systems are complex, require high investment, and steam pipelines are pressure pipelines, which have slightly lower safety. A satisfactory solution has yet to be found. Utility Model Content
[0003] The purpose of this invention is to provide a heat tracing system that utilizes the waste heat of the flue gas from the desulfurization system. This heat tracing system has a reasonable structure and can not only heat the outdoor pipelines and denitrification urea solution of the production enterprise by utilizing the waste heat of the flue gas, but also serve as a heat tracing solution for other applications. It makes full use of the waste heat of the flue gas, saves costs, and increases production capacity.
[0004] The technical solution adopted by this utility model to solve its technical problem is: a heat tracing system utilizing the waste heat of the original flue gas in a desulfurization system, comprising a flue, an outdoor pipe, and a urea solution tank, characterized in that it further includes a power component, a cold water pipe, a heat exchange coil, a hot water pipe, and a return water header. The outer walls of the flue, the outdoor pipe, and the urea solution tank are respectively wrapped with heat exchange coils. One end of the cold water pipe is connected to the power component, and the other end of the cold water pipe is connected to the water inlet of the heat exchange coil on the outer wall of the flue. One end of the hot water pipe is connected to the water outlet of the heat exchange coil on the outer wall of the flue, and the other end of the hot water pipe is connected to the water inlet of the heat exchange coil on the outer wall of the outdoor pipe and the urea solution tank. The water outlet of the heat exchange coil on the outer wall of the urea solution tank is connected to the water inlet of the return water header, and the water outlet of the return water header is connected to the power component.
[0005] Based on the above technical solution, the present invention can be further improved as follows.
[0006] Furthermore, it also includes a return water branch pipe and a heat-traced pipe, wherein the inlet end of the return water branch pipe is connected to the hot water pipe, the outlet end of the return water branch pipe is connected to the return water main pipe, and the heat-traced pipe is located on one side of the return water branch pipe.
[0007] The beneficial effects of adopting the above-mentioned further solutions are:
[0008] A return branch pipe is installed in the middle of the hot water pipe to divert the hot water in the hot water pipe to another branch pipe. Since the return branch pipe is close to the pipe being heated, the solution in the pipe being heated can be heated, which can be used to raise the temperature of other pipes that need to be heated, thus realizing the multiple utilization of flue gas waste heat recovery.
[0009] Furthermore, the power component includes a circulation pump and an expansion tank. One end of the circulation pump is connected to a water tank, and the other end of the circulation pump is connected to the expansion tank. The outlet of the expansion tank is connected to a cold water pipe.
[0010] Furthermore, a cold water supply pipe is provided on one side of the expansion tank to replenish water when water leaks from the system.
[0011] The beneficial effects of adopting the above-mentioned further solutions are:
[0012] When the system heats up, the expansion tank absorbs the excess water generated by thermal expansion; when the system cools down or leaks, the expansion tank replenishes the system with the required amount of water, thereby reducing the number of times the safety valve releases pressure and the number of times the automatic water replenishment valve replenishes water.
[0013] Furthermore, the exterior of heat exchange coil one and heat exchange coil two are respectively provided with insulation layers.
[0014] The beneficial effects of adopting the above-mentioned further solutions are:
[0015] By setting up an insulation layer, the waste heat recovered from the flue gas can be kept warm, the water temperature in the hot water pipe can be maintained for a longer period of time, and the heat exchange efficiency can be improved.
[0016] Furthermore, the exterior of the heat-traced pipe and the return water branch pipe is provided with an insulation layer.
[0017] Furthermore, thermometers are installed on the outside of the hot water pipe, the urea solution tank, and the return water header.
[0018] The beneficial effects of adopting the above-mentioned further solutions are:
[0019] The temperature of various parts of the system can be monitored in real time using multiple thermometers.
[0020] The beneficial effects of this utility model are:
[0021] This utility model utilizes a waste heat tracing system for flue gas. Multiple turns of heat exchange coil one are wound around the outside of the flue. Through heat exchange coil one, waste heat from boiler exhaust can be recovered. Since multiple turns of heat exchange coil two are wound around the outside of the outdoor pipe and the urea solution tank, hot water heated by waste heat flows through the hot water pipe into heat exchange coil two, thereby achieving heat tracing of the solution in the urea solution tank. At the same time, it can reduce the temperature inside the flue, save energy, and reduce costs.
[0022] Because a return water branch pipe is connected to the hot water pipe via a tee, a branch of the hot water in the hot water pipe is diverted to other pipes that require heat tracing, such as heating the desulfurization process water and flushing water pipes, thereby realizing the multiple utilization of waste heat recovery from the desulfurization flue gas, which is highly applicable. Attached Figure Description
[0023] Figure 1 This is a schematic diagram illustrating the principle and structure of this utility model;
[0024] In the picture:
[0025] 1. Circulating pump, 2. Expansion tank, 3. Cold water supply pipe, 4. Cold water pipe, 5. Flue, 6. Insulation layer, 7. Heat exchange coil one, 8. Hot water pipe, 9. Heat-traced pipe, 10. Urea solution tank, 11. Return water branch pipe, 12. Return water main pipe, 13. Thermometer, 14. Heat exchange coil two. Detailed Implementation
[0026] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.
[0027] Please see Figure 1 This utility model provides a technical solution: a heat tracing system utilizing the waste heat of the original flue gas from a desulfurization system, comprising a flue 5 and a urea solution tank 10, and further comprising a power unit, a cold water pipe 4, a first heat exchange coil 7, a second heat exchange coil 14, a hot water pipe 8, and a return water header 12. The outer wall of the flue 5 is wound with the first heat exchange coil 7, and the outer wall of the urea solution tank 10 is wound with the second heat exchange coil 14. The inlet end of the cold water pipe 4 is connected to the power unit, and the outlet end of the cold water pipe 4 is connected to the inlet end of the first heat exchange coil 7. The inlet end of the hot water pipe 8 is connected to the outlet end of the first heat exchange coil 7, and the outlet end of the hot water pipe 8 is connected to the inlet end of the second heat exchange coil 14. The outlet end of the second heat exchange coil 14 is connected to the inlet end of the return water header 12, and the outlet end of the return water header 12 is connected to the power unit.
[0028] High-temperature flue gas passes through flue 5, where the residual heat of the flue gas exchanges heat with the cold water in heat exchange coil 7 on the outer wall of the flue. The hot water that has undergone heat exchange in heat exchange coil 7 then enters heat exchange coil 14 outside the urea solution tank through hot water pipe 8. The hot water in heat exchange coil 14 exchanges heat with the solution in urea solution tank 10. The cooled water after heat exchange then flows back to circulation pump 1 through return water header 12.
[0029] The power components include a circulating pump 1 and an expansion tank 2. One end of the circulating pump 1 is connected to a water tank (not shown in the figure), and the other end is connected to the expansion tank 2. The outlet of the expansion tank 2 is connected to a cold water pipe 4. A cold water supply pipe 3 is also provided on one side of the expansion tank 2 to replenish water when the system leaks. The function of the expansion tank 2 is to absorb excess water generated by thermal expansion when the system heats up; and to replenish the system with the required amount of water when the system cools down or leaks, thereby reducing the number of times the safety valve releases pressure and the number of times the automatic water supply valve replenishes water.
[0030] To prevent heat loss, insulation layers 6 are provided on the outside of the heat exchange coil 7 and the heat exchange coil 14 respectively.
[0031] Thermometers 13 are respectively installed on the outside of the hot water pipe 5, the urea solution tank 10 and the return water header 12, so that the temperature inside the hot water pipe, the urea solution tank and the return water header can be observed in real time.
[0032] To improve the utilization rate of flue gas waste heat, a return water branch pipe 11 and a heat-traced pipe 9 can be installed. The heat-traced pipe and the return water branch pipe are equipped with an insulation layer. The inlet end of the return water branch pipe is connected to the hot water pipe through a tee. A return water branch pipe 11 is led out from the hot water pipe 8 for other heat tracing purposes. The outlet end of the return water branch pipe 11 is connected to the return water main pipe 12. The heat-traced pipe 9 is located on one side of the return water branch pipe 11. Heat exchange is carried out between the return water branch pipe 11 and the heat-traced pipe 9 through the temperature of the liquid in the return water branch pipe 11. The heat-traced pipe can transport the heat-traced liquid, such as desulfurization process water.
[0033] This utility model's waste heat tracing system can recover waste heat from boiler exhaust and can also trace the water pipes and the urea solution tank for flue gas denitrification, making full use of thermal energy and saving costs.
[0034] The above description is merely an illustration of some principles of this utility model. This specification is not intended to limit this utility model to the specific structure and applicable scope shown. Therefore, all possible modifications and equivalents that may be used fall within the scope of the patent application of this utility model.
[0035] Except for the technical features described in the specification, all other technical features are known to those skilled in the art.
Claims
1. A heat tracing system utilizing the waste heat of raw flue gas from a desulfurization system, comprising a flue and a urea solution tank, characterized in that, It also includes a power unit, cold water pipes, heat exchange coils, hot water pipes, and a return water header. The outer walls of the flue and the urea solution tank are respectively wound with heat exchange coils. One end of the cold water pipe is connected to the power unit, and the other end of the cold water pipe is connected to the water inlet of the heat exchange coil on the outer wall of the flue. One end of the hot water pipe is connected to the water outlet of the heat exchange coil on the outer wall of the flue, and the other end of the hot water pipe is connected to the water inlet of the heat exchange coil on the outer wall of the urea solution tank. The water outlet of the heat exchange coil on the outer wall of the urea solution tank is connected to the water inlet of the return water header, and the water outlet of the return water header is connected to the power unit.
2. A heat tracing system utilizing the waste heat of the raw flue gas from a desulfurization system according to claim 1, characterized in that, It also includes a return water branch pipe and a heat-traced pipe. The inlet end of the return water branch pipe is connected to the hot water pipe, and the outlet end of the return water branch pipe is connected to the return water main pipe. The heat-traced pipe is located on one side of the return water branch pipe.
3. A heat tracing system utilizing the waste heat of the raw flue gas from a desulfurization system according to claim 1 or 2, characterized in that, The power unit includes a circulating pump and an expansion tank. One end of the circulating pump is connected to a water tank, and the other end of the circulating pump is connected to the expansion tank. The outlet of the expansion tank is connected to a cold water pipe.
4. A heat tracing system utilizing the waste heat of the raw flue gas from a desulfurization system according to claim 3, characterized in that, The expansion tank is equipped with a cold water supply pipe on one side to replenish water when water leaks from the system.
5. A heat tracing system utilizing the waste heat of the raw flue gas from a desulfurization system according to claim 1, characterized in that, Both heat exchange coil one and heat exchange coil two are provided with an insulation layer on their exterior.
6. A heat tracing system utilizing the waste heat of the raw flue gas from a desulfurization system according to claim 2, characterized in that, The heat-traced pipe and the return water branch pipe are provided with an insulation layer.
7. A heat tracing system utilizing the waste heat of the raw flue gas from a desulfurization system according to claim 1, characterized in that, Thermometers are installed on the outside of the hot water pipe, urea solution tank and return water header.