A carbon black drying section and exhaust gas co-processing system
By designing a flue gas treatment system that integrates the carbon black drying section with the exhaust gas, the system utilizes the dried flue gas as a heat source for ammonia water evaporation and achieves uniform mixing of ammonia and flue gas. This solves the problems of complex equipment and low energy utilization in existing technologies, and realizes efficient flue gas treatment and ultra-clean emissions.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- FUJIAN LONGKING DSDN ENGINEERING CO LTD
- Filing Date
- 2025-07-03
- Publication Date
- 2026-05-26
Smart Images
Figure CN224270752U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the technical field of carbon black tail gas treatment, specifically relating to a carbon black drying section and tail gas co-flue gas treatment system. Background Technology
[0002] Carbon black production involves the incomplete combustion or pyrolysis of carbon-containing coal tar, ethylene, and other hydrocarbon organic compounds in the gas phase into a black powder. The process includes carbon black preparation, humidification and granulation, drying, VBC (Vacuum-Based Carbon Filtration) processing, and tail gas treatment. Carbon black production methods include furnace processing, tank processing, and thermal cracking. Carbon black collected in the main bag filter needs to pass through a compaction tank, wet granulator, and dryer to be processed into finished products.
[0003] The drying process typically involves burning the carbon black tail gas produced in the carbon black preparation process in a heating furnace to generate high-temperature flue gas, which is then used to dry the carbon black particles granulated in the pre-heating stage, thus producing finished carbon black particles. The flue gas inside the dryer comes into direct or indirect contact with the moist carbon black, causing some carbon black flue gas to mix with the flue gas exiting the dryer, ultimately forming the drying section flue gas. Due to the high-temperature combustion of the carbon black tail gas, a large amount of pollutants such as nitrogen oxides are generated.
[0004] The exhaust gas process is used to treat the excess carbon black exhaust gas with a certain calorific value generated in the carbon black production process. This exhaust gas is burned to generate heat for waste heat power generation or steam generation. However, due to the high temperature of combustion, the exhaust gas will generate a large amount of thermal nitrogen oxides and other pollutants.
[0005] Direct emission of the flue gas and exhaust gas from the drying section into the atmosphere would cause environmental pollution, impacting the entire ecosystem and human health. Therefore, denitrification, desulfurization, and dust removal treatment is necessary for the flue gas and exhaust gas from the carbon black drying section. Existing treatment methods involve separate treatment devices for the flue gas and exhaust gas, resulting in high overall costs and complex operation and maintenance. Especially in production with multiple production lines, having separate treatment devices for each line's drying section leads to cumbersome equipment, low energy efficiency, and poor operational performance. Utility Model Content
[0006] This invention addresses the shortcomings of existing technologies by providing a flue gas treatment system that integrates the carbon black drying section with the exhaust gas.
[0007] To achieve the above objectives, the technical solution of this utility model is as follows:
[0008] A carbon black drying section and exhaust gas co-treatment system includes a drying flue gas passage, an exhaust gas passage, a waste heat boiler, a rectifying and equalizing device, an SCR denitrification reactor, and a post-treatment device. The drying flue gas passage has an integrated ammonia evaporator. The waste heat boiler includes a first waste heat recovery section and a second waste heat recovery section. The outlet of the exhaust gas passage is connected to the inlet of the first waste heat recovery section. The outlet of the first waste heat recovery section and the outlet of the drying flue gas passage are connected to the inlet of the SCR denitrification reactor via the rectifying and equalizing device. The outlet of the SCR denitrification reactor is connected to the inlet of the second waste heat recovery section, and the outlet of the second waste heat recovery section is connected to the post-treatment device.
[0009] Optionally, it also includes a bypass channel connected between the outlet of the first waste heat recovery section and the outlet of the SCR denitrification reactor, and the bypass channel is equipped with a flow control device.
[0010] Optionally, the ammonia evaporator is a horizontal ammonia evaporator, placed in the flow path of the dry flue gas channel, and uses the dry flue gas as the evaporation heat source.
[0011] Optionally, the drying flue gas channel is used to receive drying flue gas with a temperature of 200℃ to 250℃ generated by the carbon black drying section.
[0012] Optionally, the drying flue gas channel is used to receive drying flue gas generated by the carbon black drying sections of multiple production lines, and each production line's carbon black drying section is equipped with a dryer.
[0013] Optionally, a high-temperature fan is provided at the front end of the ammonia evaporator in the drying flue gas passage.
[0014] Optionally, the first waste heat recovery section is used to process the high-temperature exhaust gas input from the exhaust gas passage, and then output exhaust boiler flue gas with a temperature reduced to 350℃~420℃ after heat exchange.
[0015] Optionally, the rectifying and distributing device is used to mix the flue gas from the tail gas boiler and the dry flue gas and ammonia gas input from the dry flue gas channel evenly and output mixed flue gas with a temperature of 320℃~390℃; the SCR denitrification reactor is used to receive the mixed flue gas and output denitrified flue gas.
[0016] Optionally, the second waste heat recovery section is used to process the denitrified flue gas to a mixed flue gas with an output temperature reduced to 150°C to 170°C after heat exchange.
[0017] Optionally, the post-treatment device includes an integrated desulfurization and dust removal device and a chimney connected in sequence. A blower is provided in the connecting channel between the inlet of the integrated desulfurization and dust removal device and the outlet of the second waste heat recovery section, and an induced draft fan is provided in the connecting channel between the outlet of the integrated desulfurization and dust removal device and the inlet of the chimney.
[0018] The beneficial effects of this utility model are as follows:
[0019] 1) It meets the common denitrification needs of multiple different flue gases, and can realize unified flue gas treatment and emission of the entire carbon black plant, reducing the number of denitrification devices, reducing investment and floor space, and making system maintenance simpler.
[0020] 2) Dry flue gas is used as the heat source for ammonia water evaporation, and the uniform mixing of ammonia and flue gas is achieved through a rectifier and distribution device. This eliminates the need for an additional ammonia water evaporation system and ammonia injection grid required for SCR denitrification, simplifying the SCR denitrification configuration and reducing the complexity of the system.
[0021] 3) The flue gas in the drying section does not require a separate waste heat boiler. It is used together with the waste heat boiler for carbon black tail gas to recover waste heat. The two-stage setup reduces the impact of flue gas mixing on the thermal efficiency of the waste heat boiler, improves energy utilization efficiency, and also reduces operating costs and improves economic efficiency.
[0022] Other features and beneficial effects of this invention will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing this invention. Attached Figure Description
[0023] Figure 1 This is a schematic diagram of a flue gas treatment system for carbon black drying section and tail gas, according to one embodiment.
[0024] Figure 2 for Figure 1 Flow path diagram of a medium-temperature waste heat boiler;
[0025] Figure 3 This is a schematic diagram of a carbon black drying section and exhaust gas co-processing system according to another embodiment. Detailed Implementation
[0026] The present invention will be further explained below with reference to the accompanying drawings and specific embodiments. The accompanying drawings are merely illustrative to facilitate understanding of the invention, and their specific proportions can be adjusted according to design requirements. The front-to-back relationships of the devices in the system described herein should be understood by those skilled in the art as being defined in terms of the direction of flue gas flow.
[0027] refer to Figure 1 and Figure 2An embodiment of a carbon black drying section and tail gas co-treatment system is installed in a carbon black production line. It includes a drying flue gas passage 1, a tail gas passage 2, a waste heat boiler 3, a rectifier and distribution device 4, an SCR denitrification reactor 5, and a post-treatment device. The post-treatment device includes an integrated desulfurization and dust removal device 6 and a chimney 7. An ammonia evaporator 8 is built into the drying flue gas passage 1. The waste heat boiler 3 includes a first waste heat recovery section and a second waste heat recovery section. The outlet of the tail gas passage 2 is connected to the inlet a of the first waste heat recovery section. The outlet b of the first waste heat recovery section and the outlet of the drying flue gas passage 1 are connected to the inlet of the SCR denitrification reactor 5 through the rectifier and distribution device 4. The outlet of the SCR denitrification reactor 5 is connected to the inlet c of the second waste heat recovery section. The outlet d of the second waste heat recovery section is sequentially connected to the integrated desulfurization and dust removal device 6 and the chimney 7. Arrows in the figure indicate the flow direction of the flue gas and thus show the flue gas inlets and outlets of each device.
[0028] The drying flue gas passage 1 is used to receive the drying flue gas generated by the carbon black drying section. The carbon black drying section dries the carbon black in the dryer 9, generating drying flue gas at a temperature of 200℃~250℃. This drying flue gas is introduced into the drying flue gas passage 1 via a high-temperature fan 10 located at the front end of the ammonia evaporator 8 and then enters the ammonia evaporator 8. The ammonia evaporator 8 is a horizontal ammonia evaporator, placed in the flow path of the drying flue gas passage 8, and uses the drying flue gas as the evaporation heat source. The drying flue gas evaporates the ammonia water into ammonia gas, forming a mixture of drying flue gas and ammonia gas. By using the introduced drying flue gas as the heat source for ammonia evaporation, the heat of the drying flue gas itself is utilized, eliminating the need for additional ammonia evaporation fans and ammonia injection grids.
[0029] The exhaust gas passage 2 is used to receive the high-temperature exhaust gas generated by the combustion in the combustion furnace, and its temperature can typically reach 1000-1100℃. The first waste heat recovery section of the waste heat boiler 3 is used to process the high-temperature exhaust gas input from the exhaust gas passage 2, and after heat exchange, the output temperature of the boiler exhaust gas A is reduced to 350℃-420℃.
[0030] The flue gas from exhaust boilers and the dried flue gas have the following characteristics:
[0031] 1) The flue gas temperature is high, exceeding that of ordinary coal-fired boilers;
[0032] 2) The flue gas has a high moisture content, generally exceeding 30%;
[0033] 3) The flue gas dust contains some unburned carbon black dust, which is light in weight, small in particle size, and highly sticky;
[0034] 4) The NOx concentration in the flue gas is as high as 600-1000 mg / Nm³. 3 ;
[0035] 5) The SO2 concentration in the flue gas reached as high as 1300 mg / Nm³.3 above.
[0036] The rectifying and uniform distribution device 4 is used to uniformly mix the flue gas A from the tail gas boiler and the dry flue gas and ammonia input from the dry flue gas channel 8, and output mixed flue gas B at a temperature of 320℃~390℃. This temperature meets the requirements of the high-temperature SCR denitrification process and achieves uniform distribution of ammonia and flue gas. The SCR denitrification reactor 5 is used to receive the mixed flue gas B. In the 5-SCR denitrification reactor 5, the mixed flue gas B utilizes the action of the SCR catalyst to promote the reaction of NH3 and NOx in the flue gas to generate H2O and N2, achieving high-temperature NOx removal and obtaining denitrified flue gas C with NOx concentration meeting emission standards. The second waste heat recovery section of the waste heat boiler 3 is used to process the denitrified flue gas C through heat exchange, and output mixed flue gas D with a temperature reduced to 150℃~170℃, achieving further waste heat recovery from the dry flue gas and tail gas boiler flue gas. A blower 11 is installed in the connecting channel between the inlet of the integrated desulfurization and dust removal device 6 and the outlet d of the second waste heat recovery section. An induced draft fan 12 is installed in the connecting channel between the outlet of the integrated desulfurization and dust removal device 6 and the inlet of the chimney 7. The mixed flue gas D is introduced into the integrated desulfurization and dust removal device 6 through the blower 11 to achieve the ultra-clean emission standards for SO2 and dust in the flue gas, and then introduced into the chimney 7 by the induced draft fan 12 for discharge into the atmosphere. A circulation channel 13 is also provided between the connecting channel from the induced draft fan 12 to the chimney 7 and the inlet of the integrated desulfurization and dust removal device 6 for the recirculation of desulfurized flue gas, so as to meet the flue gas volume and pressure of the desulfurization tower. The circulation channel 13 is equipped with a circulating air regulating device 14 to regulate the air volume and air pressure at the inlet of the desulfurization tower, ensuring that the flue gas in the desulfurization tower does not collapse.
[0037] The first and second waste heat recovery sections can utilize known heat exchange structures to achieve heat exchange with water / steam, such as economizers, air preheaters, and superheaters. The dried flue gas is introduced into an external SCR denitrification device, rather than directly into the waste heat boiler. This avoids the impact of the dried flue gas on the boiler superheater and evaporator, improves the recovery and utilization of waste heat from the dried flue gas, and allows for combined flue gas denitrification treatment with the waste heat boiler flue gas. Furthermore, a bypass channel 15 is provided between the outlet b of the first waste heat recovery section and the outlet of the SCR denitrification reactor. The bypass channel 15 is equipped with a flow control device 16, which regulates the flow rate and pressure of the flue gas entering the inlet c of the second waste heat recovery section. This reduces system resistance and avoids problems such as a significant increase in resistance due to a large amount of flue gas entering the second waste heat recovery section, as well as vibrations in the flue and system caused by increased flow velocity.
[0038] refer to Figure 2In another embodiment, the drying flue gas channel 1 is used to receive the drying flue gas generated from the carbon black drying sections of multiple production lines. Each carbon black drying section of the production line is equipped with a dryer 9, thereby achieving unified treatment of the drying section flue gas and tail gas from multiple production lines. Taking a carbon black flue gas treatment device with an annual production capacity of 100,000 tons / year as an example, there are two main carbon black production lines in the plant, each production line corresponds to one dryer line, and there is a one-to-one correspondence between the production lines and the dryer lines. There is one waste heat boiler, and the flue gas volume of each drying section is between 15,000 and 20,000 Nm³. 3 / h, high-temperature exhaust gas volume 80,000~100,000 Nm³ 3 The NOx concentration in both dry flue gas and exhaust gas is ~700 mg / Nm³ / h. 3 By sharing a single denitrification treatment unit with the carbon black drying sections of the two production lines and the flue gas from the tail gas boiler, the total flue gas volume to be treated is 110,000–140,000 Nm³. 3 / h, using external SCR denitrification, with the catalyst layer arranged in a "3+1" configuration, using ammonia water as a reducing agent, utilizing the hot flue gas in the drying section to evaporate the ammonia water into ammonia gas, and mixing it evenly with the flue gas from the tail gas boiler, can achieve a NOx removal efficiency of 93%, ensuring that the NOx concentration emitted from the chimney is ≤50mg / Nm³. 3 To meet ultra-clean emission requirements, the denitrified mixed flue gas undergoes two-stage heat exchange before entering the downstream dry desulfurization and dust removal unit, achieving SO2 ≤ 35 mg / Nm³. 3 Dust ≤10mg / Nm 3 Emissions meet standards.
[0039] The above embodiments are only used to further illustrate the carbon black drying section and exhaust gas co-treatment system of this utility model. However, this utility model is not limited to the embodiments. Any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of this utility model shall fall within the protection scope of this utility model.
Claims
1. A flue gas treatment system for carbon black drying section and tail gas, characterized in that: The system includes a drying flue gas duct, a tail gas flue gas duct, a waste heat boiler, a rectifier and distribution device, an SCR denitrification reactor, and a post-treatment device. The drying flue gas duct has an integrated ammonia evaporator. The waste heat boiler includes a first waste heat recovery section and a second waste heat recovery section. The outlet of the tail gas flue gas duct is connected to the inlet of the first waste heat recovery section. The outlet of the first waste heat recovery section and the outlet of the drying flue gas duct are connected to the inlet of the SCR denitrification reactor through the rectifier and distribution device. The outlet of the SCR denitrification reactor is connected to the inlet of the second waste heat recovery section. The outlet of the second waste heat recovery section is connected to the post-treatment device.
2. The carbon black drying section and tail gas co-flue gas treatment system according to claim 1, characterized in that: It also includes a bypass channel, which is connected between the outlet of the first waste heat recovery section and the outlet of the SCR denitrification reactor, and the bypass channel is equipped with a flow control device.
3. The carbon black drying section and tail gas co-flue gas treatment system according to claim 1, characterized in that: The ammonia evaporator is a horizontal ammonia evaporator, which is placed in the flow path of the dry flue gas channel and uses the dry flue gas as the evaporation heat source.
4. The carbon black drying section and tail gas co-flue gas treatment system according to claim 1, characterized in that: The drying flue gas channel is used to receive drying flue gas with a temperature of 200℃~250℃ generated by the carbon black drying section.
5. The carbon black drying section and tail gas co-flue gas treatment system according to claim 1, characterized in that: The drying flue gas channel is used to receive the drying flue gas generated by the carbon black drying sections of multiple production lines, and each production line's carbon black drying section is equipped with a dryer.
6. The carbon black drying section and tail gas co-flue gas treatment system according to claim 1, characterized in that: A high-temperature fan is installed at the front end of the ammonia evaporator in the drying flue gas channel.
7. The carbon black drying section and tail gas co-flue gas treatment system according to claim 1, characterized in that: The first waste heat recovery section is used to process the high-temperature exhaust gas input from the exhaust gas channel, and then output the exhaust gas boiler flue gas with a temperature reduced to 350℃~420℃ after heat exchange.
8. The carbon black drying section and tail gas co-flue gas treatment system according to claim 7, characterized in that: The rectifying and distributing device is used to mix the flue gas from the tail gas boiler and the dry flue gas and ammonia gas input from the dry flue gas channel evenly and output mixed flue gas with a temperature of 320℃~390℃; the SCR denitrification reactor is used to receive the mixed flue gas and output denitrified flue gas.
9. The carbon black drying section and tail gas co-flue gas treatment system according to claim 8, characterized in that: The second waste heat recovery section is used to process the denitrified flue gas, which has a reduced output temperature of 150°C to 170°C after heat exchange.
10. The carbon black drying section and tail gas co-flue gas treatment system according to claim 1, characterized in that: The post-treatment device includes an integrated desulfurization and dust removal device and a chimney connected in sequence. A blower is provided in the connecting channel between the inlet of the integrated desulfurization and dust removal device and the outlet of the second waste heat recovery section, and an induced draft fan is provided in the connecting channel between the outlet of the integrated desulfurization and dust removal device and the inlet of the chimney.