Coke oven raw gas and flue gas waste heat comprehensive recycling system and method
By combining the waste heat recovery system of coke oven waste gas and flue gas, high-temperature flue gas is used to heat the desalination and oxygenation water and share the water supply system, the problem of limited sensible heat recovery range and insufficient steam output of the waste heat recovery system of coke oven waste gas and flue gas is solved, and the medium-pressure steam output is improved and operating costs are reduced.
Patent Information
- Application Number
- CN202510482953.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-17
- Publication Date
- 2025-07-08
AI Technical Summary
In the prior art, the waste heat recovery systems of coke oven waste gas and flue gas have problems with limited sensible heat recovery range and insufficient steam output, respectively, making it difficult to achieve efficient comprehensive utilization.
Combining the waste heat recovery system of coke oven waste gas and flue gas, the desalination water is heated by high-temperature flue gas through the water supply heater and sent to the riser heat exchange system. Combining the flue waste heat furnace and the riser heat exchange system share the water supply system, increasing the medium-pressure steam output, and cooling the forced circulation pump and drum discharge sewage to recover heat.
It has achieved the conversion of 30-40% of the waste heat of the flue gas into medium-pressure steam, increasing the quantity of high-quality steam, reducing the number of equipment, reducing the operating and maintenance costs, and reducing the consumption of medium-pressure steam by 15%, and recovering heat by more than 1.5%.
Smart Images
Figure CN120274549A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of the recovery and utilization of raw coke oven gas and flue gas. More specifically, the present invention relates to a system and method for comprehensively recovering the waste heat of raw coke oven gas and flue gas in a coke oven. Background Art
[0002] Raw coke oven gas is a by-product generated during the process of converting coal into coke at high temperature in the carbonization chamber of a coke oven. When it flows out of the carbonization chamber, the temperature is 650 - 850°C. At present, part of its sensible heat can be recovered through the waste heat recovery system of the riser pipe to produce medium- and low-pressure saturated steam or superheated steam, reducing the consumption of steam or gas during the production process of the coking plant and also reducing the ammonia water circulation volume for cooling the raw coke oven gas, thereby achieving the purpose of energy conservation and carbon reduction. However, due to the large amount of tar contained in the raw coke oven gas, tar is prone to condensation when the gas temperature is lower than 500°C and adheres to the wall of the heat exchanger. Therefore, the range of sensible heat recovery of the raw coke oven gas is limited.
[0003] Coke oven flue gas is the medium- and low-temperature flue gas after the combustion of fuel gas (generally coke oven gas or blast furnace gas) in the combustion chamber of a coke oven to heat the carbonization chamber, and the temperature is generally 200 - 280°C. Due to its low temperature, currently, the heat is generally recovered through a flue waste heat boiler to produce low-pressure saturated steam of 0.6 - 0.8 MPa.
[0004] The waste heat recovery system of raw coke oven gas can produce medium-pressure steam with relatively high quality, but the steam output is limited. And the flue gas also contains a large amount of waste heat, but generally, the flue gas waste heat recovery system can only produce low-pressure saturated steam. Therefore, it is necessary to provide a system and method for comprehensively recovering the waste heat of raw coke oven gas and flue gas in a coke oven, which can combine the waste heat recovery system of raw coke oven gas and the waste heat recovery system of flue gas to increase the output of medium-pressure steam and improve the economic benefits. Summary of the Invention
[0005] An object of the present invention is to solve at least the above problems and provide at least the advantages described later.
[0006] To achieve these objects and other advantages in accordance with the present invention, there is provided a system for comprehensively recovering the waste heat of raw coke oven gas and flue gas in a coke oven, comprising: A flue gas waste heat recovery system, which includes a feed water heater and a flue waste heat boiler respectively communicated with the outlet of the flue; A raw coke oven gas waste heat recovery system, which includes a feed water system and a riser pipe heat exchange system; the feed water system supplies demineralized and deoxygenated water to the flue waste heat boiler and the riser pipe heat exchange system respectively; The feed water heater is used to heat the demineralized and deoxygenated water supplied from the feed water system to the riser pipe heat exchange system by using high-temperature flue gas.
[0007] Preferably, the feed water system includes a demineralized water tank, a deaeration water pump, and a deaerator that are sequentially connected by pipelines; the water outlet of the deaerator is divided into two paths, one path is connected to the waste heat boiler feed water pump, and the other path is connected to the steam drum feed water pump; the water outlet of the steam drum feed water pump is connected to the water inlet of the feed water heater, and the water outlet of the feed water heater is connected to the water inlet of the riser tube heat exchange system; a part of the low-pressure steam generated by the flue gas waste heat boiler is connected to the deaerator through a pipeline.
[0008] Preferably, the riser tube heat exchange system includes a steam drum, a forced circulation pump, and a riser tube heat exchanger; the water outlet of the feed water heater is connected to the water inlet of the steam drum, the water outlet of the steam drum is connected to the water inlet of the riser tube heat exchanger through the forced circulation pump, and the steam-water mixture generated by the riser tube heat exchanger is connected to the water return port of the steam drum.
[0009] Preferably, a cooling component is further provided on the forced circulation pump, the water outlet of the deaeration water pump is connected to the water inlet of the cooling component, and the water outlet of the cooling component is connected to the water inlet of the deaerator.
[0010] Preferably, a heat exchanger is provided in the demineralized water tank, and the blowdown water from the steam drum is discharged after heat exchange through the heat exchanger.
[0011] Another object of the present invention is to provide a method for comprehensively recovering and utilizing the waste heat of coke oven raw gas and flue gas, using the comprehensive waste heat recovery and utilization system for coke oven raw gas and flue gas, including: The flue gas output from the outlet of the flue is divided into two parts, one part is transported to the feed water heater, and the other part is transported to the flue gas waste heat boiler; the demineralized and deaerated water supplied from the feed water system to the riser tube heat exchange system is heated by the feed water heater to the saturation temperature corresponding to the pressure in the steam drum, and the gas content rate of the demineralized and deaerated water is not less than 15%, and then sent into the steam drum; at the same time, the steam generated by the riser tube heat exchanger is also sent into the steam drum; the medium-pressure steam discharged from the steam outlet of the steam drum is externally supplied for heating; the demineralized and deaerated water in the steam drum is sent back to the riser tube heat exchanger through the forced circulation pump; a part of the low-pressure steam generated by the flue gas waste heat boiler is transported to the deaerator for use, and the other part is externally supplied for heating.
[0012] Preferably, a cooling component is further provided on the forced circulation pump, and the demineralized water output from the water outlet of the deaeration water pump in the feed water system is first transported to the cooling component, cooled by the forced circulation pump, and then sent into the deaerator.
[0013] Preferably, a heat exchanger is provided in the demineralized water tank, and the blowdown water discharged from the steam drum is first transported to the heat exchanger and then discharged from the water outlet of the heat exchanger.
[0014] The present invention has at least the following beneficial effects: 1. The waste heat comprehensive recovery and utilization system and method for coke oven raw gas and flue gas provided by the present invention. The feed water heater uses high-temperature flue gas to heat the demineralized and deoxygenated water supplied from the feed water system to the riser heat exchange system, which can increase the output of medium-pressure steam in the riser heat exchange system. Furthermore, 30 - 40% of the waste heat of the flue gas can be converted from low-pressure steam to medium-pressure steam, increasing the quantity of high-quality steam. And the flue gas waste heat furnace and the riser heat exchange system share the feed water system, which can reduce the number of equipment and the operation and maintenance costs.
[0015] 2. The waste heat comprehensive recovery and utilization system and method for coke oven raw gas and flue gas provided by the present invention. By introducing the low-pressure steam from the flue gas waste heat furnace to the deaerator, the consumption of medium-pressure steam can be reduced by about 15%; by using demineralized water to cool the blowdown water of the steam drum in the riser waste heat system, more than 1% of the heat can be recovered in terms of medium-pressure steam measurement; by using demineralized water to cool the forced circulation pump, more than 1.5% of the heat can be recovered in terms of medium-pressure steam measurement.
[0016] Other advantages, objectives and features of the present invention will be partially reflected by the following description and partially understood by those skilled in the art through the research and practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS
[0017] Figure 1 It is a structural block diagram of the waste heat comprehensive recovery and utilization system for coke oven raw gas and flue gas of the present invention; DETAILED DESCRIPTION OF THE EMBODIMENTS
[0018] The following further detailed description of the present invention is made in conjunction with the drawings, so that those skilled in the art can implement it according to the description in the specification.
[0019] It should be noted that the experimental methods described in the following embodiments are all conventional methods unless otherwise specified, and the reagents and materials can be obtained from commercial channels unless otherwise specified; in the description of the present invention, the orientation or positional relationship indicated by terms such as "horizontal", "longitudinal", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, and does 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 cannot be construed as a limitation of the present invention.
[0020] As Figure 1 shown, the present invention provides a waste heat comprehensive recovery and utilization system for coke oven raw gas and flue gas, including: A flue gas waste heat recovery system 20, which includes a feed water heater 21 and a flue gas waste heat furnace 22 respectively communicated with the outlet of the flue; The waste gas heat recovery system 10 includes a feed water system and a riser heat exchange system; the feed water system supplies demineralized and deoxidized water to the flue gas waste heat boiler 22 and the riser heat exchange system respectively; The feed water heater 21 is used to heat the demineralized and deoxidized water supplied from the feed water system to the riser heat exchange system by using high-temperature flue gas.
[0021] In this technical solution, by adding the feed water heater 21 at the outlet of the flue, the high-temperature flue gas in the flue is used to heat the demineralized and deoxidized water in the feed water heater 21, and the demineralized and deoxidized water in the feed water heater 21 is supplied to the riser heat exchange system to increase the output of medium-pressure steam in the riser heat exchange system, thereby realizing the conversion of 30-40% of the waste heat of the flue gas into medium-pressure steam from low-pressure steam and increasing the quantity of high-quality steam. And the flue gas waste heat boiler and the riser heat exchange system share the feed water system, which can reduce the number of equipment and the operation and maintenance cost. Preferably, compared with the flue gas waste heat boiler, the feed water heater 21 is arranged closer to the outlet of the flue, so that the high-temperature flue gas in the flue enters the feed water heater 21 first, and the remaining flue gas enters the flue gas waste heat boiler for heat exchange to produce low-pressure steam.
[0022] In another technical solution, the feed water system 21 includes a demineralized water tank 11, a deoxidation water pump 12, and a deoxidizer 13 connected in sequence through pipelines; the outlet of the deoxidizer 13 is divided into two paths, one path is connected to the waste heat boiler feed water pump 23, and the other path is connected to the steam drum feed water pump 14; the outlet of the steam drum feed water pump 14 is connected to the inlet of the feed water heater 21, and the outlet of the feed water heater 21 is connected to the inlet of the riser heat exchange system; a part of the low-pressure steam generated by the flue gas waste heat boiler 22 is connected to the deoxidizer 13 through a pipeline. The demineralized and deoxidized water provided by the feed water system is divided into two paths at the outlet of the deoxidizer 13 and is respectively transported to the flue gas waste heat boiler 22 and the riser heat exchange system through the waste heat boiler feed water pump 23 and the steam drum feed water pump 14. The flue gas waste heat boiler 22 can be connected to the inlet of the deoxidizer 13 by accessing a branch pipeline at its outlet. Compared with the traditional method of introducing medium-high pressure steam generated by the riser heat exchange system into the deoxidizer 13, supplying steam to the deoxidizer 13 by the flue gas waste heat boiler 22 can further reduce the consumption of medium-pressure steam.
[0023] In another technical solution, the riser heat exchange system includes a steam drum 15, a forced circulation pump 17, and a riser heat exchanger 16; the water outlet of the feed water heater 21 is connected to the water inlet of the steam drum 15, the water outlet of the steam drum 15 is connected to the water inlet of the riser heat exchanger 16 through the forced circulation pump 17, and the steam-water mixture generated by the riser heat exchanger 16 is connected to the water return port of the steam drum. The feed water heater 21 heats the demineralized and deoxidized water supplied to the steam drum 15. The density of water decreases as the temperature rises, and the density difference from the steam transported from the heat exchanger 17 into the steam drum 15 increases, which is beneficial to the efficient separation of the separator, can accelerate the steam generation rate of the steam drum 15, and further increase the output of high-quality medium-pressure steam. During actual use, as Figure 1 shown, multiple steam drums 15 and multiple riser heat exchangers 16 can be arranged in parallel.
[0024] In another technical solution, a cooling component is provided on the forced circulation pump 17. The water outlet of the deaerating water pump 12 is connected to the water inlet of the cooling component, and the water outlet of the cooling component is connected to the water inlet of the deaerator 14. The pump cooling water of the forced circulation pump 17 is cooled by the demineralized water pressurized and supplied by the deaerating water pump 12, and the heat generated during the operation of the forced circulation pump 17 is recovered. The cooling component can adopt a water-cooled heat dissipation device commonly used in water pumps, which is not limited here.
[0025] In another technical solution, a heat exchanger is provided in the demineralized water tank 1, and the blowdown water of the steam drum 15 is discharged after heat exchange through the heat exchanger. The blowdown port of the steam drum 15 is connected to the water inlet of the heat exchanger through a pipeline, the water outlet of the heat exchanger is connected to a blowdown water recovery device, and the heat generated by the heat exchanger is recovered by the demineralized water in the demineralized water tank 1.
[0026] The present invention also provides a method for comprehensively recovering and utilizing the waste heat of coke oven raw gas and flue gas, using the comprehensive waste heat recovery and utilization system for coke oven raw gas and flue gas, including: The flue gas output from the outlet of the flue, a part of which is transported to the feed water heater 21, and the other part is transported to the flue waste heat furnace 22; the demineralized and deoxidized water provided to the riser heat exchange system from the feed water system is heated by the feed water heater 21 to the saturation temperature corresponding to the pressure in the steam drum 15, and the gas content rate of the demineralized and deoxidized water is not less than 15%, and then sent into the steam drum 15; at the same time, the steam generated by the riser heat exchanger 16 is also sent into the steam drum 15; the medium-pressure steam discharged from the steam outlet of the steam drum 15 is externally supplied for heating; the demineralized and deoxidized water in the steam drum 15 is sent back into the riser heat exchanger 16 through the forced circulation pump 17; a part of the low-pressure steam generated by the flue waste heat furnace 22 is transported to the deaerator 13 for use, and the other part is externally supplied for heating.
[0027] The demineralized and deoxygenated water supplied to the steam drum 15 is heated by the feed water heater 21 and heated to the saturation temperature corresponding to the pressure in the steam drum 15, so that the evaporation process in the steam drum 15 is more uniform, the water droplets entrained in the steam are reduced, and the steam quality is higher. Moreover, the density difference with the steam can be increased, the separation efficiency of the separator in the steam drum can be improved, and thus the production efficiency of medium-pressure steam can be improved. Furthermore, the feed water temperature is close to the wall temperature of the steam drum 15, which can reduce the thermal stress caused by the temperature difference and extend the service life of the equipment. Through on-site tests, 30-40% of the waste heat of the flue gas can be converted from low-pressure steam into medium-pressure steam, increasing the quantity of high-quality steam. By sending the low-pressure steam from the flue gas waste heat boiler 22 to the deaerator 13, the consumption of medium-pressure steam can be reduced by about 15%.
[0028] Furthermore, a cooling component is provided on the forced circulation pump 17. The demineralized water output from the outlet of the deaerator pump 12 in the feed water system is first transported to the cooling component, cooled by the cooling component, and then sent to the deaerator 13. By cooling the water pump of the riser waste heat system with demineralized water, more than 1.5% of the heat can be recovered according to the measurement of medium-pressure steam.
[0029] A heat exchanger is provided in the demineralized water tank 11. The blowdown water discharged from the steam drum 15 is first transported to the heat exchanger and then discharged from the outlet of the heat exchanger. By cooling the blowdown water of the steam drum 15 in the riser waste heat system with demineralized water, more than 1% of the heat can be recovered according to the measurement of medium-pressure steam.
[0030] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and the embodiments. It can be fully applied to various fields suitable for the present invention. For those familiar with the field, additional modifications can be easily made. Therefore, without departing from the general concept defined by the claims and the equivalent scope, the present invention is not limited to the specific details and the examples shown and described here.
Claims
1. A comprehensive waste heat recovery and utilization system for coke oven raw gas and flue gas, characterized in that, Comprising: A flue gas waste heat recovery system, which includes a feed water heater and a flue waste heat furnace respectively communicated with the outlet of the flue. A raw coke oven gas waste heat recovery system, which includes a feed water system and a riser pipe heat exchange system; the feed water system supplies demineralized and deaerated water to the flue waste heat furnace and the riser pipe heat exchange system respectively. The feed water heater is used to heat the demineralized and deaerated water supplied from the feed water system to the riser pipe heat exchange system by using high-temperature flue gas.
2. The waste heat comprehensive recovery and utilization system for coke oven raw gas and flue gas according to claim 1, characterized in that, The feed water system includes a demineralized water tank, a deaeration water pump, and a deaerator connected in sequence through pipelines; the outlet of the deaerator is divided into two paths, one path is connected to the waste heat furnace feed water pump, and the other path is connected to the steam drum feed water pump; the outlet of the steam drum feed water pump is connected to the inlet of the feed water heater, and the outlet of the feed water heater is connected to the inlet of the riser pipe heat exchange system; a part of the low-pressure steam generated by the flue waste heat furnace is connected to the deaerator through a pipeline.
3. The waste heat comprehensive recovery and utilization system of coke oven raw gas and flue gas according to claim 2, wherein The riser pipe heat exchange system includes a steam drum, a forced circulation pump, and a riser pipe heat exchanger; the outlet of the feed water heater is connected to the inlet of the steam drum, the outlet of the steam drum is connected to the inlet of the riser pipe heat exchanger through the forced circulation pump, and the steam-water mixture generated by the riser pipe heat exchanger is connected to the water return port of the steam drum.
4. The waste heat comprehensive recovery and utilization system for coke oven raw gas and flue gas according to claim 3, characterized in that, A cooling component is also provided on the forced circulation pump, the outlet of the deaeration water pump is connected to the inlet of the cooling component, and the outlet of the cooling component is connected to the inlet of the deaerator.
5. The waste heat comprehensive recovery and utilization system for coke oven raw gas and flue gas according to claim 3, characterized in that, A heat exchanger is provided in the demineralized water tank, and the blowdown water from the steam drum is discharged after heat exchange through the heat exchanger.
6. A method for comprehensive recovery and utilization of waste heat from coke oven raw gas and flue gas, using the comprehensive waste heat recovery and utilization system for coke oven raw gas and flue gas as described in claim 3, characterized in that, Comprising: The flue gas output from the outlet of the flue, a part of which is transported to the feed water heater, and the other part is transported to the flue waste heat furnace; the demineralized and deaerated water supplied from the feed water system to the riser pipe heat exchange system is heated by the feed water heater to the saturation temperature corresponding to the pressure in the steam drum, and the gas content rate of the demineralized and deaerated water is not less than 15%, and then sent into the steam drum; at the same time, the steam generated by the riser pipe heat exchanger is also sent into the steam drum; the medium-pressure steam discharged from the steam outlet of the steam drum is externally supplied for heating; the demineralized and deaerated water in the steam drum is sent into the riser pipe heat exchanger again through the forced circulation pump; a part of the low-pressure steam generated by the flue waste heat furnace is transported to the deaerator for use, and the other part is externally supplied for heating.
7. The method for comprehensive recovery and utilization of waste heat from raw coke oven gas and flue gas according to claim 6, characterized in that, A cooling component is also provided on the forced circulation pump, and the demineralized water output from the outlet of the deaeration water pump in the feed water system is first transported to the cooling component, cooled the forced circulation pump, and then sent into the deaerator.
8. The waste heat comprehensive recovery and utilization system for coke oven raw gas and flue gas according to claim 6, characterized in that, A heat exchanger is provided in the demineralized water tank, and the blowdown water discharged from the steam drum is first transported to the heat exchanger and then discharged from the outlet of the heat exchanger.