High-temperature flue gas powder suspension heat exchange waste heat utilization system

Abstract

The utility model discloses a high-temperature flue gas powder suspension heat exchange waste heat utilization system which comprises a high-temperature flue gas pipe, a flue gas cooling system, a normal-temperature gas heating system, a powder medium, a suspension heat exchanger, an unloader, a flue gas cooling pipe, a dust remover, a normal-temperature gas pipe, a heating gas pipe and an elevator. The flue gas cooling system and the normal-temperature gas heating system are respectively formed by connecting a plurality of suspension heat exchangers in series; each suspension heat exchanger comprises a feeding pipe, a gas inlet pipe suspension cavity, a gas outlet pipe, a deposition tank and a discharging pipe. According to the powder suspension heat exchange waste heat utilization system, a powder medium serves as a heat accumulator, cooling of high-temperature flue gas and heating of normal-temperature gas are achieved through the flue gas cooling system and the normal-temperature gas heating system respectively, and the heat value of the high-temperature flue gas is firstly transmitted to the powder medium through the flue gas cooling system; and the heat of the heated high-temperature powder medium is transferred to the normal-temperature gas through the normal-temperature gas heating system, so that the gas preheating function is achieved, and the high-temperature flue gas waste heat recovery rate of the system is high.

Description

Technical Field

[0001] This utility model relates to the field of high-temperature flue gas treatment, and in particular to a high-temperature flue gas powder suspension heat exchange waste heat utilization system for recovering and utilizing the waste heat of high-temperature flue gas generated by industrial kiln combustion. Background Technology

[0002] my country is a major industrial country, producing more than half of the world's industrial raw materials such as steel, cement, and glass. The production of these raw materials utilizes industrial kilns, consuming large quantities of energy sources such as coal and natural gas. The combustion of these energy sources generates substantial amounts of high-temperature flue gas, which has extremely high waste heat recovery value. Currently, my country is vigorously developing a low-carbon economy, and energy conservation and carbon reduction are crucial tasks for the development of Chinese industrial enterprises. Therefore, effectively utilizing the waste heat from high-temperature flue gas has significant economic and social value.

[0003] Currently, high-temperature flue gas treatment in my country often employs fume hoods and waste heat boilers to recover waste heat from the flue gas, converting its calorific value into pressurized steam for power generation. Even with a 60% waste heat recovery rate and a 30% conversion rate for steam power generation, after deducting the waste heat loss from the low-temperature flue gas, the overall waste heat utilization rate is only about 20%. Therefore, it is evident that the waste heat utilization efficiency of high-temperature flue gas in current industrial systems remains at a low level, urgently requiring the development of new waste heat recovery and utilization technologies.

[0004] Traditional high-temperature flue gas waste heat utilization is based on heat exchange between high-temperature flue gas and water, converting the flue gas into pressurized steam. The main components of high-temperature flue gas are often N2, CO2, and H2O, meaning that oxygen in the air has been consumed and converted into CO2 and H2O, and it contains a high concentration of dust, rendering it devoid of usable material components. High-temperature flue gas emissions often correspond to the air or oxygen required for combustion. Using high-temperature flue gas to heat materials is the most efficient way to utilize waste heat resources; directly using it to heat air or oxygen would be the best approach to achieving waste heat utilization. In industrial production, high-temperature flue gas has been used to dry and heat solid raw materials such as ores, but there are still few cases of directly heating air with high-temperature flue gas. The main reason is the low efficiency of heat conduction between gases, and convection heat transfer, which mixes high-temperature flue gas and air, cannot effectively utilize the oxygen within, resulting in even lower energy utilization. Smelting and other production enterprises often need to directly use coal gas or other combustion to heat the hot blast stove. Because the high-temperature flue gas contains a lot of dust, the heat storage function of the checker bricks in the hot blast stove will be blocked by dust, thus losing its heat storage function and becoming unusable. Summary of the Invention

[0005] Purpose of the utility model: This utility model provides a high-temperature flue gas powder suspension heat exchange waste heat utilization system, thereby maximizing the utilization of high-temperature flue gas waste heat.

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

[0007] A high-temperature flue gas powder suspension heat exchange waste heat utilization system is characterized by comprising: a high-temperature flue gas pipe, a flue gas cooling system, a normal temperature gas heating system, a powder medium, a unloader, a flue gas cooling pipe, a dust collector, a normal temperature gas pipe, a heating gas pipe, and a hoist.

[0008] The flue gas cooling system and the ambient temperature gas heating system are each composed of multiple suspended heat exchangers connected in series. Each suspended heat exchanger includes a feed pipe, an air inlet pipe, a suspension chamber, an air outlet pipe, a sedimentation tank, and a discharge pipe. The suspension chamber carries the powder medium. An air inlet pipe is set on the upper side of the suspension chamber and is connected to the feed pipe. An air outlet pipe is set in the middle of the top of the suspension chamber. A sedimentation tank is set below the suspension chamber and a discharge pipe is set in the middle of the bottom of the sedimentation tank. For two adjacent suspended heat exchangers in the flue gas cooling system and the ambient temperature gas heating system, the discharge pipe of the previous suspended heat exchanger is connected to the feed pipe of the next suspended heat exchanger, and the air outlet pipe of the next suspended heat exchanger is connected to the air inlet pipe of the previous suspended heat exchanger.

[0009] The inlet pipe of the lowest suspension heat exchanger in the flue gas cooling system is connected to the high-temperature flue gas pipe. The outlet pipe of the highest suspension heat exchanger in the flue gas cooling system is connected to the dust collector through the flue gas cooling pipe. The inlet pipe of the lowest suspension heat exchanger in the ambient temperature gas heating system is connected to the ambient temperature gas pipe. The outlet pipe of the highest suspension chamber in the ambient temperature gas heating system is connected to the heating gas pipe. The outlet pipe of the lowest suspension heat exchanger in the flue gas cooling system is connected to the inlet pipe of the highest suspension heat exchanger in the ambient temperature gas heating system through the unloader. The outlet pipe of the lowest suspension heat exchanger in the ambient temperature gas heating system is connected to the loading end of the elevator. The unloading end of the elevator is connected to the inlet pipe of the highest suspension heat exchanger in the flue gas cooling system.

[0010] Furthermore, the high-temperature flue gas pipe, feed pipe, air inlet pipe, air outlet pipe, discharge pipe, flue gas cooling pipe, normal temperature gas pipe, and heating gas pipe are all steel structure pipes.

[0011] Furthermore, the inner walls of the high-temperature flue pipe, feed pipe, air inlet pipe, air outlet pipe, discharge pipe, and heating pipe are all provided with fire-resistant and heat-insulating linings, with a thickness of 50-300mm.

[0012] Furthermore, the suspension cavity is a steel cylindrical barrel, and the inner wall of the suspension cavity is provided with a fire-resistant insulation layer with a thickness of not less than 50mm.

[0013] Furthermore, the sedimentation tank is a steel cone, and the inner wall of the sedimentation tank is provided with a fire-resistant insulation layer with a thickness of not less than 50mm.

[0014] Furthermore, the unloader is a high-temperature resistant rotary unloader.

[0015] Furthermore, the dust collector is a bag filter dust collector.

[0016] Beneficial Effects: This powder suspension heat exchange waste heat utilization system uses powder as the heat storage medium. It employs a flue gas cooling system and a room-temperature gas heating system to cool the high-temperature flue gas and heat the room-temperature gas, respectively. The calorific value of the high-temperature flue gas is first transferred to the powder medium through the flue gas cooling system. Then, the heated high-temperature powder medium transfers its heat to the room-temperature gas through the room-temperature gas heating system, thus achieving gas preheating. The system boasts a high high-temperature flue gas waste heat recovery rate. In terms of waste heat recovery, this system achieves an effective utilization rate of over 80% for high-temperature flue gas waste heat, compared to only about 20% for traditional processes, representing a 5-fold increase in efficiency. Regarding the treatment of high-temperature flue gas, it enables sedimentation and cooling. The treated high-temperature flue gas can be directly discharged through a bag filter, significantly reducing the system investment and operating costs of traditional dust removal processes.

[0017] This powder suspension heat exchange waste heat recovery system can be used for high-temperature flue gas waste heat recovery in industrial kilns such as metallurgy and building materials. It boasts advantages such as wide application range, low system investment, reliable equipment operation, high waste heat recovery efficiency, and low-cost ultra-clean flue gas emissions. This invention has significant technological and market advantages and can be applied to fields such as steel, non-ferrous metals, cement, glass, power, and waste incineration, possessing enormous market potential. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of a high-temperature flue gas powder suspension heat exchange waste heat utilization system.

[0019] In the diagram: 1-High-temperature flue gas pipe, 2-Flue gas cooling system, 3-Ambient temperature gas heating system, 4-Powder medium, 5-Suspension heat exchanger, 6-Feed pipe, 7-Inlet pipe, 8-Suspension chamber, 9-Outlet pipe, 10-Sedimentation tank, 11-Outlet pipe, 12-Unloader, 13-Flue gas cooling pipe, 14-Dust collector, 15-Ambient temperature gas pipe, 16-Heating gas pipe, 17-Elevator. Detailed Implementation

[0020] The present invention will be further explained below with reference to the accompanying drawings.

[0021] like Figure 1 As shown, the present invention discloses a high-temperature flue gas powder suspension heat exchange waste heat utilization system, including a high-temperature flue gas pipe 1, a flue gas cooling system 2, a normal temperature gas heating system 3, a powder medium 4, a unloader 12, a flue gas cooling pipe 13, a dust collector 14, a normal temperature gas pipe 15, a heating gas pipe 16, and a hoist 17.

[0022] The flue gas cooling system 2 and the ambient temperature gas heating system 3 are each composed of multiple suspended heat exchangers 5 connected in series. Each suspended heat exchanger 5 includes a feed pipe 6, an air inlet pipe 7, a suspension chamber 8, an air outlet pipe 9, a sedimentation tank 10, and a discharge pipe 11. The suspension chamber 8 carries the powder medium 4. The air inlet pipe 7 is set on the upper side of the suspension chamber 8 and is connected to the feed pipe 6. The air outlet pipe 9 is set in the middle of the top of the suspension chamber 8. The sedimentation tank 10 is set below the suspension chamber 8 and the discharge pipe 11 is set in the middle of the bottom of the sedimentation tank 10. For two adjacent suspended heat exchangers 5 in the flue gas cooling system 2 and the ambient temperature gas heating system 3, the discharge pipe 11 of the previous suspended heat exchanger 5 is connected to the feed pipe 6 of the next suspended heat exchanger 5, and the air outlet pipe 9 of the next suspended heat exchanger 5 is connected to the air inlet pipe 7 of the previous suspended heat exchanger 5.

[0023] The inlet pipe 7 of the lowest suspension heat exchanger 5 in the flue gas cooling system 2 is connected to the high-temperature flue gas pipe 1. The outlet pipe 9 of the highest suspension heat exchanger 5 in the flue gas cooling system 2 is connected to the dust collector 14 through the flue gas cooling pipe 13. The inlet pipe 7 of the lowest suspension heat exchanger 5 in the ambient temperature gas heating system 3 is connected to the ambient temperature gas pipe 15. The outlet pipe 9 of the highest suspension chamber 8 in the ambient temperature gas heating system 3 is connected to the heating gas pipe 16. The outlet pipe 11 of the lowest suspension heat exchanger 5 in the flue gas cooling system 2 is connected to the inlet pipe 6 of the highest suspension heat exchanger 5 in the ambient temperature gas heating system 3 through the unloader 12. The outlet pipe 11 of the lowest suspension heat exchanger 5 in the ambient temperature gas heating system 3 is connected to the feeding end of the elevator 17. The discharging end of the elevator 17 is connected to the feeding pipe 6 of the highest suspension heat exchanger 5 in the flue gas cooling system 2.

[0024] Among them, the high-temperature flue gas pipe 1, feed pipe 6, air inlet pipe 7, air outlet pipe 9, discharge pipe 11, flue gas cooling pipe 13, ambient temperature gas pipe 15, and heating gas pipe 16 are all steel structure pipes. The inner walls of the high-temperature flue gas pipe 1, feed pipe 6, air inlet pipe 7, air outlet pipe 9, discharge pipe 11, and heating gas pipe 16 are all lined with fire-resistant and heat-insulating linings with a thickness of 50–300 mm. The suspension chamber 8 is a steel cylindrical barrel, and its inner wall is lined with a fire-resistant and heat-insulating layer with a thickness of not less than 50 mm. The sedimentation tank 10 is a steel cone, and its inner wall is lined with a fire-resistant and heat-insulating layer with a thickness of not less than 50 mm. The unloader 12 is a high-temperature resistant rotary unloader with a high-temperature operating temperature of not less than 500℃. The dust collector 14 is a bag filter dust collector. The powder medium is solid powder particles with a maximum particle size not exceeding 3 mm. The preferred powder media composition is iron oxide-based or alumina-based material, with the TFe content in the iron oxide-based material not less than 40% and the alumina content in the alumina-based material not less than 40%.

[0025] The working process of this high-temperature flue gas powder suspension heat exchange waste heat utilization system includes the following steps:

[0026] 1) High-temperature flue gas is introduced into the inlet pipe of the lowest suspension heat exchanger in the flue gas cooling system through the high-temperature flue gas pipe. The powder medium, after being lifted by the elevator, is transported to the feed pipe of the highest suspension heat exchanger in the flue gas cooling system. The high-temperature flue gas gradually rises, and the powder medium gradually sinks, with both flowing in a counter-current manner. The trajectory of the high-temperature flue gas and powder medium in a single suspension heat exchanger is shown in step 2).

[0027] 2) The high-temperature flue gas introduced from the inlet pipe of the suspension heat exchanger and the powder medium falling from the outlet pipe of the previous suspension heat exchanger meet at the intersection of the two pipes. Under the induced draft of the high-temperature flue gas, the powder medium enters the suspension chamber from the inlet pipe of the suspension heat exchanger. Under gravity, the powder medium settles in the sedimentation tank and then falls through the outlet pipe into the inlet pipe of the next suspension heat exchanger. The high-temperature flue gas continues to rise under the induced draft and enters the inlet pipe of the previous suspension heat exchanger through the outlet pipe.

[0028] 3) The high-temperature flue gas and the powder medium travel along the trajectory described above, and the flue gas with residual heat and the lower-temperature powder medium undergo intense heat exchange. As the high-temperature flue gas rises, it gradually cools down to a certain temperature and then passes through the outlet pipe of the uppermost suspension heat exchanger of the flue gas cooling system, the flue gas cooling pipe, and the dust collector before being discharged in compliance with standards.

[0029] 4) After the powder medium is heated to a certain temperature through heat exchange in the flue gas cooling system, it flows downward from the outlet pipe of the last suspension heat exchanger in the flue gas cooling system, and is uniformly and stably transported by the unloader to the inlet pipe of the first suspension heat exchanger in the ambient temperature gas heating system, and gradually flows downward. The ambient temperature gas is blown in through the inlet pipe of the last suspension heat exchanger in the ambient temperature gas heating system through the ambient temperature gas pipe, and gradually flows upward.

[0030] 5) The high-temperature powder medium entering the ambient temperature gas heating system and the ambient temperature gas blown into the ambient temperature gas heating system move in opposite directions. Their trajectories are the same as those in step 2) of the flue gas cooling system above.

[0031] 6) During the upward movement of the ambient temperature gas, it encounters the high-temperature powder medium. The residual heat of the high-temperature powder medium and the lower-temperature ambient temperature gas undergo a vigorous heat exchange. The ambient temperature gas gradually heats up to a certain temperature during its upward movement and is eventually discharged from the outlet pipe of the uppermost suspension heat exchanger of the ambient temperature gas heating system, connected to the heated gas pipe for external use. The high-temperature powder medium gradually cools down to a certain temperature during its downward movement and eventually falls from the outlet pipe of the lowermost suspension heat exchanger into the bottom of the elevator. The powder medium is then lifted by the elevator to the uppermost suspension heat exchanger of the top flue gas cooling system.

[0032] 7) Following steps 1) to 6), a flue gas cooling system was used to cool the high-temperature flue gas and meet the temperature requirements of the bag filter, achieving ultra-clean emissions. Simultaneously, the powder medium was heated, providing a stable heat source for the subsequent ambient temperature gas heating system. The heated gas can be externally supplied for reuse. The powder medium is recycled within the flue gas cooling system and the ambient temperature gas heating system, realizing the utilization of waste heat from the high-temperature flue gas and ultra-clean emissions.

[0033] Specifically, high-temperature flue gas entering the flue gas cooling system through the high-temperature flue gas pipe has an initial temperature of no less than 500℃, and after passing through the flue gas cooling system, the temperature discharged through the flue gas cooling pipe does not exceed 200℃. Normal-temperature gas, after being heated by the normal-temperature gas heating system, is delivered through the heated gas pipe at a temperature of no less than 400℃.

[0034] The powder medium, after being heated by the flue gas cooling system, falls from the discharge pipe of the last suspension heat exchanger in the flue gas cooling system at a temperature not lower than 400℃. The powder medium, after being cooled by the ambient temperature gas heating system, falls from the discharge pipe of the last suspension heat exchanger in the ambient temperature gas heating system at a temperature not exceeding 200℃.

[0035] The residence time of the powder medium in the flue gas cooling system and the ambient temperature gas heating system is 30~150 seconds, and the heat exchange cycle of the whole system is 80~360 seconds.

[0036] The above description is only a preferred embodiment of the present utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present utility model, and these improvements and modifications should also be considered within the protection scope of the present utility model.

Claims

1. A high-temperature flue gas powder suspension heat exchange waste heat utilization system, characterized in that... : Including high temperature flue gas pipe (1), flue gas cooling system (2), ambient temperature gas heating system (3), powder medium (4), unloader (12), flue gas cooling pipe (13), dust collector (14), ambient temperature gas pipe (15), heating gas pipe (16), elevator (17); The flue gas cooling system (2) and the ambient temperature gas heating system (3) are each composed of multiple suspension heat exchangers (5) connected in series. The suspension heat exchanger (5) includes a feed pipe (6), an air inlet pipe (7), a suspension chamber (8), an air outlet pipe (9), a sedimentation tank (10), and a discharge pipe (11). The suspension chamber (8) carries the powder medium (4). The air inlet pipe (7) is set on the upper side of the suspension chamber (8). The air inlet pipe (7) is connected to the feed pipe (6). The air outlet pipe is set in the middle of the top of the suspension chamber (8). (9) A sedimentation tank (10) is set below the suspension chamber (8), and a discharge pipe (11) is set in the middle of the bottom of the sedimentation tank (10). For two adjacent suspension heat exchangers (5) of the flue gas cooling system (2) and the ambient temperature gas heating system (3), the discharge pipe (11) of the previous suspension heat exchanger (5) is connected to the feed pipe (6) of the next suspension heat exchanger (5), and the air outlet pipe (9) of the next suspension heat exchanger (5) is connected to the air inlet pipe (7) of the previous suspension heat exchanger (5). The inlet pipe (7) of the lowest suspension heat exchanger (5) of the flue gas cooling system (2) is connected to the high-temperature flue gas pipe (1), and the outlet pipe (9) of the highest suspension heat exchanger (5) of the flue gas cooling system (2) is connected to the dust collector (14) through the flue gas cooling pipe (13). The inlet pipe (7) of the lowest suspension heat exchanger (5) of the ambient temperature gas heating system (3) is connected to the ambient temperature gas pipe (15), and the outlet pipe (9) of the highest suspension chamber (8) of the ambient temperature gas heating system (3) is connected to the heating gas pipe. (16) The discharge pipe (11) of the last suspension heat exchanger (5) of the flue gas cooling system (2) is connected to the feed pipe (6) of the last suspension heat exchanger (5) of the ambient temperature gas heating system (3) through the unloader (12). The discharge pipe (11) of the last suspension heat exchanger (5) of the ambient temperature gas heating system (3) is connected to the feeding end of the elevator (17). The unloading end of the elevator (17) is connected to the feeding pipe (6) of the last suspension heat exchanger (5) of the flue gas cooling system (2).

2. The high-temperature flue gas powder suspension heat exchange waste heat utilization system according to claim 1, characterized in that... The high-temperature flue gas pipe (1), feed pipe (6), air inlet pipe (7), air outlet pipe (9), discharge pipe (11), flue gas cooling pipe (13), normal temperature gas pipe (15), and heating gas pipe (16) are all steel structure pipes.

3. The high-temperature flue gas powder suspension heat exchange waste heat utilization system according to claim 2, characterized in that... The inner walls of the high-temperature flue gas pipe (1), feed pipe (6), air inlet pipe (7), air outlet pipe (9), discharge pipe (11), and heating gas pipe (16) are all provided with fire-resistant and heat-insulating linings with a thickness of 50-300mm.

4. The high-temperature flue gas powder suspension heat exchange waste heat utilization system according to claim 1, characterized in that... The suspension cavity (8) is a steel cylindrical barrel, and the inner wall of the suspension cavity (8) is provided with a fire-resistant insulation layer with a thickness of not less than 50mm.

5. A high-temperature flue gas powder suspension heat exchange waste heat utilization system according to claim 1, characterized in that... The sedimentation tank (10) is a steel cone, and the inner wall of the sedimentation tank (10) is provided with a fire-resistant insulation layer with a thickness of not less than 50mm.

6. A high-temperature flue gas powder suspension heat exchange waste heat utilization system according to claim 1, characterized in that... The unloader (12) is a high-temperature resistant rotary unloader.

7. A high-temperature flue gas powder suspension heat exchange waste heat utilization system according to claim 1, characterized in that... The dust collector (14) is a bag filter.

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