Flue gas dust removal device for methanol-to-olefin industry
By designing a flue gas dust removal device for the methanol-to-olefin industry, the problems of acid slurry corrosion equipment and water mist discharge in wet dust removal devices are solved, and the optimization effects of equipment protection, environmental protection emissions and sewage treatment are achieved.
Patent Information
- Application Number
- CN202421291972.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-06-06
- Publication Date
- 2025-03-21
- Estimated Expiration
- 2034-06-06
AI Technical Summary
The wet dust removal device in the existing methanol-to-olefin industry has the problem that the slurry is acid-corrosive and the water vapor is discharged from the outside, which affects the equipment life and environmentally friendly emissions.
A flue gas dust removal device is designed, including a flue gas scrubbing system, a water mist collection system, a slurry solid-liquid separation system and an alkali injection system. The dust removal of flue gas and neutralization of slurry is achieved through the combination of a foam removal tower, a water mist collection device, a filter, a filter press and an alkali injection system.
It effectively slows down equipment corrosion, thoroughly collects water mist, reduces energy consumption, meets environmental protection emission requirements, and reduces the burden of sewage treatment.
Smart Images
Figure CN222641574U_ABST
Abstract
Description
Technical Field
[0001] The utility model belongs to the technical field of methanol to olefins, and specifically relates to a flue gas dust removal device used in the methanol to olefins industry. Background Art
[0002] While methanol generates ethylene, propylene and other main products in the reactor under the action of the catalyst, about 1.3-1.8% of the methanol in the feed will be converted into coke and attached to the catalyst, causing the catalyst to be deactivated. In order to ensure the continuous progress of the reaction process, the deactivated catalyst is sent to the regenerator for coke regeneration to restore its activity, and the restored catalyst is returned to the reactor to continue the reaction. The catalyst continuously completes the process of deactivation and regeneration in the reactor and the regenerator.
[0003] The regenerator of the methanol to olefins unit is used to burn the catalyst deactivated in the methanol reaction process under the action of the main wind. Since the methanol to olefins reaction process has the characteristics of shape-selective catalysis, the coke on the catalyst is generally converted into carbon monoxide and carbon dioxide by adopting an oxygen-poor incomplete regeneration method. The catalyst still retains part of the coke and returns to the reactor to continue the reaction. The regenerated flue gas formed by the incomplete combustion of the coke on the catalyst in the regenerator is sent to the dust removal facility for treatment after oxygen-enriched combustion in the CO incinerator and then meets the emission standards.
[0004] The methanol to olefins regeneration process is carried out in a fluidized bed. The catalyst is separated by primary, secondary and tertiary cyclone separators in the regenerator. Due to the limitations of the cyclone separators, catalyst fine powder smaller than 5μm is inevitably entrained by the flue gas into the subsequent system during the regeneration process. With the stringent requirements for environmental emissions, it has become increasingly urgent to add dust removal facilities to treat the flue gas to meet emission standards.
[0005] At present, the wet method is used to remove dust from the regeneration flue gas of the methanol to olefins industry. During the operation of the wet method, there are problems such as acidic slurry corroding the equipment and white mist of water vapor discharged, which are specifically manifested in:
[0006] 1. The pH of the slurry after the regeneration flue gas is washed with water is about 2-3. The strongly acidic slurry will corrode the equipment, shorten the life of the equipment, and affect the stable and long-term operation of the device.
[0007] 2. After the flue gas is wet-dust-removed, the flue gas carries water mist and is discharged through the chimney and falls to the ground, causing ice on the road in winter. Deicing increases the workload, and the water mist is lost in the atmosphere, increasing water consumption;
[0008] 3. The slurry containing the spent catalyst is discharged into the sewage pool, increasing the burden of downstream sewage treatment. Utility Model Content
[0009] In order to solve the existing problems that the slurry of the wet dust removal device is acidic and corrosive to the equipment and white mist of water vapor is discharged externally, the utility model provides a flue gas dust removal device for the methanol to olefins industry.
[0010] In order to achieve the above purpose, the utility model is implemented through the following technical solutions:
[0011] A flue gas dust removal device for methanol to olefins industry, comprising a flue gas washing system, a water mist collection system, a slurry solid-liquid separation system and an alkali injection system; wherein the flue gas washing system comprises a defoaming tower with an inlet quenching pipe and a slurry circulation pump, and a defoaming net is arranged inside the defoaming tower; the slurry circulation pump is provided with two outlets, the flow rate of the first outlet is 3.5-5 t / h, and the slurry is sent to the slurry solid-liquid separation system for liquid-solid separation; the flow rate of the second outlet is 800-1000 t / h, and the slurry pressure of the two outlets is 0.2-0.3 Mpa; the defoaming net is a two-layer structure, which is used to remove free water mist in the regenerated flue gas, and each layer of the defoaming net is formed by stacking steel meshes, each layer is 80-120 mm high, and the mesh number of the steel mesh is 40-60; the water mist The collection system consists of a water mist collection device and a water mist collection pump with circulating cooling water. The water mist collection device is connected to the inlet of the water mist collection pump, and the outlet of the water mist collection pump is connected to the defoaming tower. The slurry solid-liquid separation system consists of a filter, a filter press and a waste catalyst collection tank arranged below the filter press. The filter inlet is connected to the first outlet of the slurry circulation pump. The filter is provided with a top clear liquid outlet and a bottom turbid liquid outlet. The top clear liquid outlet is connected to the defoaming tower, and the bottom turbid liquid outlet is connected to the filter press. The alkali injection system consists of an alkali liquid buffer tank, an alkali liquid pump and an alkali liquid mixer. The alkali liquid buffer tank is connected to the inlet of the alkali liquid pump, and the alkali liquid pump outlet is connected to the second outlet of the slurry circulation pump. The alkali liquid and the slurry are mixed in the alkali liquid mixer to obtain a weakly alkaline slurry which enters the inlet quenching pipe.
[0012] The regenerated flue gas from the regenerator is incinerated in a multi-stage cyclone separator, a CO incinerator, and heat is taken from a waste heat boiler, and then quenched and cooled before entering the defoamer tower through an inlet quenching pipe; the washing water in the initial stage of the device operation is injected into the defoamer tower by external deoxygenated water, and the catalyst particles and dust entrained in the regenerated flue gas are washed by the washing water; the regenerated flue gas after the catalyst particles are washed contacts the defoamer net during the rising process, and the water mist in the regenerated flue gas condenses into water droplets and then drips downward; the regenerated flue gas after most of the water mist is removed by the defoamer net enters the water mist collection system, and the remaining water mist in the regenerated flue gas is collected by the water mist collection device; the water collected by the water mist collection device is pressurized by the water mist collection pump and returned to the defoamer tower at a position lower than the defoamer net, and is used as washing water together with the water from the defoamer net; the catalyst dust entrained in the regenerated flue gas is washed by the washing water to form a slurry, which is divided into two paths after being pressurized by the slurry circulation pump, and the slurry at the second outlet of the slurry circulation pump is mixed with the alkali solution from the alkali injection system to obtain a weak alkaline slurry The weak alkaline slurry enters the inlet quenching tube in three ways through three nozzles evenly distributed inside the inlet quenching tube. The weak alkaline slurry sprayed from the nozzles diffuses evenly and radially under the action of its own rotating centrifugal force, and seals the inlet pipeline cavity of the foam area of the inlet quenching tube from the center to the outside. The regenerated flue gas turbulently contacts with the surface of a large amount of rapidly updated weak alkaline slurry, and the catalyst particles and dust entrained in the regenerated flue gas are captured by the weak alkaline slurry. The regenerated flue gas and the weak alkaline slurry are quenched and cooled and enter the defoaming tower; the regenerated flue gas after the catalyst particles are captured contacts the defoaming net during the rising process, and enters the water mist collection system after most of the water mist in the regenerated flue gas is initially removed; the slurry at the first outlet of the slurry circulation pump enters the filter to obtain clear liquid and turbid liquid, the clear liquid at the top returns to the defoaming tower, and the turbid liquid at the bottom enters the filter press for filtration, and the obtained dry catalyst enters the waste catalyst collection tank for collection, and the purified flue gas obtained after the water mist is completely removed is discharged through the chimney, thereby realizing flue gas purification and catalyst collection.
[0013] Specifically, two filters are provided, one in operation and one in standby, and the filter is used to filter catalyst fine powder below 5 μm. Two filter presses are provided, one in operation and one in standby.
[0014] Compared with the prior art, the advantages of the utility model are as follows:
[0015] 1. An alkali injection system is added to inject alkaline substances into the slurry to neutralize the acidic substances generated by flue gas washing, ensuring that the slurry is weakly alkaline and slowing down equipment corrosion;
[0016] 2. A water mist collection device is added to completely collect the water mist in the regenerated flue gas, solving the problem of white water vapor mist in the exhaust, which not only reduces energy consumption but also meets environmental emission requirements;
[0017] 3. A slurry solid-liquid separation system has been added to separate the slurry into solid and liquid, reducing the impact of direct discharge of high-solid wastewater on downstream sewage treatment. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] In order to more clearly illustrate the specific implementation of the utility model or the technical solution in the prior art, the following is a brief introduction to the drawings required for the specific implementation or the prior art description. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, each element or part is not necessarily drawn according to the actual scale.
[0019] Figure 1 : A schematic structural diagram of a flue gas dust removal device for the methanol to olefins industry of the utility model;
[0020] In the figure: inlet quenching pipe 1, defoaming tower 2, water mist collecting device 3, chimney 4, defoaming net 5, slurry circulation pump 6, filter 7, filter press 8, waste catalyst collecting tank 9, alkali solution buffer tank 10, alkali solution pump 11, alkali solution mixer 12, water mist collecting pump 13; all of them are well-known and commonly used devices in the art. DETAILED DESCRIPTION
[0021] In order to clearly and completely describe the technical solution and its specific working process of the utility model, the specific implementation methods of the utility model are as follows in conjunction with the accompanying drawings of the specification:
[0022] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.
[0023] In the present utility model, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.
[0024] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the utility model. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.
[0025] Example 1
[0026] The following is a detailed description of the working of a flue gas dust removal device for the methanol to olefins industry provided in this embodiment, which is as follows:
[0027] 650~700℃, 40000~50000Nm generated in the methanol to olefins regenerator 3 / h of flue gas, after separation by multi-stage cyclone separator, catalyst fine powder less than 20μm is entrained by flue gas into CO incinerator for combustion. After combustion, oxygen-enriched regeneration flue gas containing 8% (V / V) CO2 and 6% (V / V) O2 is cooled to 140-200℃ after heat removal by waste heat boiler and enters inlet quenching pipe 1. The regeneration flue gas at 140-200℃ is quenched to 50-60℃ in inlet quenching pipe 1 and then enters defoaming tower 2. The washing water in the initial stage of the device operation is injected into the deoxygenation tower by external deoxygenation water. In the foam tower 2, the catalyst particle dust entrained in the regenerated flue gas is washed by washing water; the regenerated flue gas after the catalyst particles are washed contacts the defoaming net 5 in the process of rising (the defoaming net 5 is a two-layer structure, each layer is composed of stacked steel wire meshes, each layer is 100 mm high, and the mesh number of the steel wire mesh is 50), and the regenerated flue gas after most of the water mist is initially removed by the defoaming net 5 enters the water mist collecting device 3, and the water mist collecting device 3 is provided with a circulating cooling water inlet and outlet, and the regenerated flue gas is further cooled to below 40°C by the circulating cooling water. The circulating cooling water flow rate is controlled at 2000-3000 t / h. The water mist collecting device 3 is connected to the inlet of the water mist collecting pump 13. When the liquid level of the water mist collecting device 3 reaches 50%, the water mist collecting pump 13 is started. After the water mist collecting pump 13 pressurizes the water to 0.3-0.5 MPa, it returns to the defoaming tower 2 and is used as washing water together with the water from the defoaming net 5. The catalyst dust entrained in the regenerated flue gas is washed by the washing water to form a slurry. The temperature of the slurry is 40-50°C.
[0028] The outlet of the slurry circulation pump 6 is set to two routes. The flow rate of the first outlet is 3.5-5 t / h, and the slurry is sent to the subsequent slurry solid-liquid separation system for liquid-solid separation; the flow rate of the second outlet is 800-1000 t / h, and after mixing with the alkali solution, it is quenched through the inlet quenching pipe 1 and then returned to the defoaming tower 2; the slurry pressures of the two routes are both 0.2-0.3 MPa.
[0029] The slurry of 0.2-0.3Mpa, 800-1000t / h and suspended matter concentration of 250-500mg / L after being pressurized by the slurry circulation pump 6 is mixed with the alkali solution after passing through the second outlet of the slurry circulation pump 6, and enters the inlet quenching tube 1 in three ways through three nozzles evenly distributed inside the inlet quenching tube 1. The slurry sprayed from the nozzles diffuses evenly and radially under the action of its own rotating centrifugal force, and seals the pipeline cavity of the foam area of the inlet quenching tube 1 from the center to the outside. The regenerated flue gas turbulently contacts the surface of a large amount of rapidly renewed 40-45°C slurry, and the catalyst particle dust entrained in the regenerated flue gas is captured and quenched together to 50-60°C. The slurry flows from the inside of the inlet quenching tube 1 to the bottom of the defoaming tower 2 to continue to participate in the circulation washing.
[0030] The slurry solid-liquid separation system includes a filter 7, a filter press 8 and a waste catalyst collection tank 9. The slurry with a flow rate of 3.5 to 5 t / h and a suspended matter concentration of 250 to 500 mg / L at the first outlet of the slurry circulation pump 6 enters the filter 7. The outlet of the filter 7 is divided into two paths. The clear liquid at the top returns to the defoaming tower 2, and the turbid liquid at the bottom enters the filter press 8 for filtration.
[0031] Two filters are provided, one for operation and one for standby. Two filter presses 8 are provided, one for operation and one for standby. The filter 7 and the filter press 8 are set with automatic control programs, and filtering and filter pressing are performed continuously.
[0032] A waste catalyst collecting tank 9 is provided below the filter press 8. The dry catalyst filtered by the filter press 8 enters the waste catalyst collecting tank 9, and the dry catalyst is bagged for post-processing.
[0033] The alkali injection system includes an alkali liquid buffer tank 10, an alkali liquid pump 11 and an alkali liquid mixer 12. The alkali liquid buffer tank 10 is connected to the inlet of the alkali liquid pump 11, and the outlet of the alkali liquid pump 11 is connected to the second outlet of the slurry circulation pump 6. The alkali liquid and the slurry are mixed in the alkali liquid mixer 12 and then enter the inlet quenching pipe 1.
[0034] The alkali liquid buffer tank 10 has a liquid level control of 50%, and the alkali liquid pump 11 changes the amount of alkali liquid injected into the defoaming tower 2 by adjusting the stroke to adjust the slurry pH to 8-9 to ensure that the equipment is not corroded. The alkali liquid is a sodium hydroxide solution with a mass fraction of 20%, and the temperature of the alkali liquid is room temperature.
[0035] The particulate matter content in the purified flue gas after washing and water mist collection is less than 10mg / Nm3 , far meeting the national standard emission requirements. At the same time, the pH of the slurry increased from 2-3 in the early stage to 8-9, and the pH of the slurry was flexibly controllable.
[0036] The application of the technical solution of the utility model solves the problems of poor operation effect of the sewage stripping system and substandard quality of purified water delivered at the existing stage.
[0037] The above description is only a preferred embodiment of the utility model and is not intended to limit the utility model. For those skilled in the art, the utility model may have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the utility model shall be included in the protection scope of the utility model.
[0038] The preferred embodiments of the present invention are described in detail above in conjunction with the accompanying drawings. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, and these simple modifications all belong to the protection scope of the present invention.
[0039] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present utility model will not further describe various possible combinations.
[0040] In addition, various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.
Claims
1. A flue gas dust removal device for methanol to olefins industry, characterized in that: The invention is composed of a flue gas washing system, a water mist collection system, a slurry solid-liquid separation system and an alkali injection system; the flue gas washing system is composed of a defoaming tower (2) with an inlet quenching pipe (1) and a slurry circulation pump (6), and a defoaming net (5) is arranged inside the defoaming tower (2); the slurry circulation pump (6) is provided with two outlets, the flow rate of the first outlet is 3.5-5 t / h, the flow rate of the second outlet is 800-1000 t / h, and the slurry pressure of the two outlets is 0.2-0.3 Mpa; the water mist collection system is composed of a water mist collection device (3) with circulating cooling water and a water mist collection pump (13), the water mist collection device (3) is connected to the inlet of the water mist collection pump (13), and the outlet of the water mist collection pump (13) is connected to the defoaming tower (2); the slurry solid-liquid separation system is composed of a water mist collection device (3) with circulating cooling water and a water mist collection pump (13), the water mist collection device (3) is connected to the inlet of the water mist collection pump (13), and the outlet of the water mist collection pump (13) is connected to the defoaming tower (2); The separation system is composed of a filter (7), a filter press (8) and a waste catalyst collection tank (9) arranged below the filter press (8); the inlet of the filter (7) is connected to the first outlet of the slurry circulation pump (6), the filter (7) is provided with a top clear liquid outlet and a bottom turbid liquid outlet, the top clear liquid outlet is connected to the defoaming tower (2), and the bottom turbid liquid outlet is connected to the filter press (8); the alkali injection system is composed of an alkali liquid buffer tank (10), an alkali liquid pump (11) and an alkali liquid mixer (12), the alkali liquid buffer tank (10) is connected to the inlet of the alkali liquid pump (11), the outlet of the alkali liquid pump (11) is connected to the second outlet of the slurry circulation pump (6), the alkali liquid and the slurry are mixed in the alkali liquid mixer (12) to obtain a weakly alkaline slurry which enters the inlet quenching pipe (1).
2. A flue gas dust removal device for methanol to olefins industry according to claim 1, characterized in that: The defoaming net (5) is a two-layer structure, each layer is formed by superimposing steel wire meshes, each layer has a height of 80-120 mm, and the mesh number of the steel wire meshes is 40-60.
3. A flue gas dust removal device for methanol to olefins industry according to claim 1, characterized in that: Two filters (7) are provided, one in operation and one in standby, to filter catalyst fine powder below 5 μm; two filter presses (8) are provided, one in operation and one in standby.
4. A flue gas dust removal device for methanol to olefins industry as claimed in claim 1, characterized in that: The liquid level of the alkali solution buffer tank (10) is controlled at 50%, and the alkali solution pump (11) changes the amount of alkali solution injected into the defoaming tower (2) by adjusting the stroke to adjust the slurry pH to 8-9; the alkali solution is a sodium hydroxide solution with a mass fraction of 20%, and the temperature of the alkali solution is room temperature.
5. The flue gas dust removal device for methanol to olefins industry according to claim 1, characterized in that: Three nozzles are evenly distributed inside the inlet quenching tube (1), and the weak alkaline slurry enters the inlet quenching tube (1) in three ways through the three nozzles.