CN110745927A - Coupling separation device for removing SS (suspended substance) in catalytic cracking flue gas desulfurization wastewater - Google Patents

Abstract

The invention discloses a coupling and separation device for removing SS from catalytic cracking flue gas desulfurization wastewater, comprising a tank body, a two-stage reaction stirring coagulator, a diversion cylinder, a diversion reflection device, a mud scraper, a sludge thickening hopper and a collecting hopper. Mud return device, the two-stage reaction stirring coagulator is set on the outside of the tank body, which is communicated with the diversion cylinder through the liquid inlet pipe, and the liquid, solid and medicament enter the A diversion cylinder, a diversion reflection device is arranged below the diversion cylinder, and the inner area of the tank around the diversion cylinder and the diversion reflection device is set as a clarification area, the top of the clarification area is provided with a liquid outlet pipe, and the bottom is provided with a cone The bottom center of the bottom plate is provided with the sludge thickening bucket, and the mud scraper is provided above the periphery of the bottom plate, and the sludge collecting and returning device is provided below the bottom plate. The invention has high solid-liquid separation efficiency and good SS removal effect, and is suitable for the treatment of high-concentration fine particle solid-containing industrial wastewater.

Description

A coupling separation device for removing SS from catalytic cracking flue gas desulfurization wastewater

technical field

The invention belongs to the technical field of industrial wastewater clarification and separation, in particular to a coupling separation device for removing SS from catalytic cracking flue gas desulfurization wastewater, which is mainly used for petrochemical catalytic cracking flue gas desulfurization with high solid content, fine particle size and difficult separation Clarification and separation of solid waste water.

Background technique

At present, most of the petrochemical catalytic cracking flue gas desulfurization units in my country adopt wet desulfurization. Wet desulfurization is currently the most mature and widely used flue gas desulfurization process. Among them, the limestone/lime-gypsum wet flue gas desulfurization technology accounts for about 85% of the FGD systems put into operation in the world, and the desulfurization method of most large coal-fired generating units in my country also adopts limestone/lime-gypsum wet flue gas desulfurization. process, the desulfurization efficiency can generally reach more than 95%.

However, with the development of my country's economy and society, the amount of flue gas emissions is on the rise, becoming a prominent problem in the prevention and control of regional air pollution. To this end, in recent years, the state has implemented stricter flue gas emission control standards, which have greatly lowered the emission limits of flue gas pollutants. In order to achieve the discharge standard, the most direct solution for the existing wet desulfurization system is to increase the desulfurization liquid-gas ratio to improve the desulfurization efficiency. Due to the increase of the liquid-to-gas ratio, more droplets containing desulfurization slurry will enter the mist eliminator with the flue gas; the existing folded plate mist eliminator has a very low demisting efficiency for droplets below 20 μm, and a large number of fine mist The droplets are discharged from the chimney through the demister, and the saturated flue gas containing the desulfurization slurry droplets will precipitate condensed water with the decrease of temperature during the discharge process, and form "gypsum rain", ammonium sulfate aerosol, etc., with the escaped droplets around the desulfurization device , resulting in serious emission of particulate matter exceeding the standard, bringing new environmental problems to enterprises.

On the other hand, the current FCC flue gas desulfurization solid-containing wastewater treatment method has the following problems: First, since the catalyst particles in the FCC flue gas desulfurization solid-containing wastewater are fine, the particles with a particle size of 1.0-5 μm account for more than 76%, The solid content is as high as 0.15%-0.5%. The conventional liquid-solid precipitation method has low separation efficiency and cannot meet the requirements of the emission standard. Second, the fine filter is often blocked, so it is more difficult to meet the production requirements after raising the flue gas emission standard. Requirements for the normal operation of the device.

At the same time, considering that my country's petrochemical industry projects have high water consumption per unit and low water resource efficiency, petrochemical production units are large in scale, and water resources have become a prominent contradiction in the development of my country's petrochemical industry, a solid-liquid sedimentation separation efficiency is needed. High-efficiency separation technology with high system operation cost, low investment and small land occupation to enhance the water resources recycling system of petrochemical plants and improve the overall water resources efficiency of petrochemical production process.

SUMMARY OF THE INVENTION

The object of the present invention is to achieve the requirement of improving flue gas emission control standards in the country, overcome the defects of the above-mentioned conventional flue gas desulfurization wastewater treatment technology, and aim at the industrial characteristics of catalytic cracking flue gas desulfurization solid waste water, and consider the overall improvement The water resource efficiency of catalytic cracking flue gas desulfurization device provides a novel coupling separation device for efficiently removing SS in catalytic cracking flue gas desulfurization wastewater.

In order to achieve the above purpose, the technical scheme adopted in the present invention is: a coupling and separation device for removing FCC flue gas desulfurization wastewater SS, the device includes a tank body, a two-stage reaction stirring coagulator, a guide tube, and a guide reflection device , sludge scraper, sludge thickening hopper and sludge return device. The two-stage reaction stirring coagulator is set on the outside of the tank body, which is communicated with the diversion cylinder through the liquid inlet pipe, and the liquid, solid and medicament enter the diversion cylinder through stirring and coagulation and the backflow granular sludge after coagulation. The diversion and reflection device is arranged below the diversion cylinder, and the inner region of the tank around the diversion cylinder and the diversion and reflection device is set as a clarification area. The top of the clarification zone is provided with a liquid outlet pipe, and the bottom is provided with a cone The bottom center of the bottom plate is provided with the sludge thickening bucket, and the mud scraper is provided above the periphery of the bottom plate, and the sludge collecting and returning device is provided below the bottom plate.

As a further preference of this solution, a sloping plate for upward guiding of clarified liquid is provided below the liquid outlet pipe and in the middle and upper part of the clarification area, and the sloping plate is installed on the outer wall of the guiding cylinder and the tank body between the inner walls.

As a further preference of this solution, the liquid outlet pipe at the top of the clarification zone is located outside the tank and is connected to the liquid outlet of the water collecting weir plate.

As a further priority of this solution, the mud scraper includes a geared motor, a transmission shaft, a scraper arm and a scraper, and the scraper is located above the bottom plate at the bottom of the clarification zone.

As a further preference of this solution, the diversion cylinder is of a primary or secondary structure; the primary diversion cylinder is composed of a first-level diversion cylinder, and the upper end of the I-level diversion cylinder is fixedly connected to the top of the tank body At the center; the secondary guide tube is composed of a first-level guide tube and a II-level guide tube, and the II-level guide tube is sleeved on the periphery of the I-level guide tube.

As a further preference of this solution, the sludge collecting and returning device is used to collect the sludge with heavier specific gravity at the bottom of the clarification zone, and the sludge collected in the sludge collecting and returning device passes through its return outlet and is then lifted and returned to the double Stage reaction stirring coagulator to enhance the settling separation efficiency of the system.

As a further preference of this solution, the mud collecting and returning device is arranged at a central position between the center of the bottom of the cone-shaped bottom plate and the outer wall of the tank.

As a further preference of this scheme, the sludge thickening hopper is in the shape of a funnel, and a sludge discharge pipe is connected at the bottom; the sludge thickening hopper is used to further concentrate the sludge with light specific gravity to increase the sludge discharge concentration.

Compared with the prior art, the beneficial effects of the present invention are: based on the unique structural design of the above-mentioned high-efficiency coupling and separation technology device, the device achieves the goal of efficient separation of high-solid-containing wastewater from catalytic cracking flue gas desulfurization through the following functions:

1. Set up a fluid diversion device to strengthen the solid-liquid separation effect. The diversion cylinder is placed in the center of the clarification device, and the upper port of the diversion cylinder is provided with a liquid inlet. The upper end of the cylinder is fixedly connected to the center of the top of the tank body, and the second-level diversion cylinder structure, the second-level diversion cylinder is placed outside the first-level diversion cylinder, to solve the problem of fast flow rate, uneven water distribution and turbulence of solid waste water entering the clarification zone. Serious flow and other problems, so as to achieve efficient separation.

2. Set up sludge collection and return device to increase the concentration of return sludge. The sludge at the bottom of the clarification device is scraped into the sludge collection and return device by the scraper to increase the concentration of the return sludge, which changes the process condition of the conventional mechanical clarifier with a low return sludge concentration, so that the return sludge is mixed with liquid and solid. . The drug quickly coagulates to form large particle agglomerates to accelerate the sedimentation and achieve the purpose of high-efficiency liquid-solid separation.

3. Set up sludge thickening hopper to reduce sludge disposal. The sludge at the bottom of the clarification device is scraped into the sludge thickening hopper by the scraper for further concentration, and the sludge is concentrated to 3%, thereby reducing the amount of sludge treatment and consumption, and achieving the goal of energy saving and consumption reduction.

In summary, the coupling separation device for removing SS from FCC flue gas desulfurization wastewater has the following characteristics:

1. The solid-liquid separation efficiency is high, and the SS treatment effect is good. It is suitable for the treatment of high-concentration fine-particle solid-containing industrial wastewater.

2. It can avoid the problem that the existing flue gas desulfurization increases the liquid-to-gas ratio to improve the desulfurization effect, causing the problem that the particulate matter emitted from the flue gas exceeds the standard.

3. The waste water treatment system has low investment, small footprint and low operating costs.

4. It lays a foundation for strengthening the recycling of water resources and improving the overall efficiency of water resources in the process system.

Description of drawings

Figure 1 is a schematic diagram of the overall structure of the present invention.

Marked in the figure: 1- tank, 2- two-stage reaction stirring coagulator, 3- grade I guide cylinder, 4- grade II guide cylinder, 5- guide reflection device, 6- clarification zone, 7- Bottom plate, 8-sludge thickening hopper, 9-sludge return device, 10-liquid inlet pipe, 11-liquid outlet pipe, 12-water collecting weir plate, 13-inclined plate, 14-reduction motor, 15-transmission shaft, 16- Scraper arm, 17- Sewage pipe.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

Referring to FIG. 1 , this embodiment provides: a coupling and separation device for removing FCC flue gas desulfurization wastewater 5. A sludge scraper, a sludge thickening bucket 8 and a sludge collection and return device 9. The two-stage reaction stirring coagulator 2 is arranged on the outside of the tank body 1, which is communicated with the guide tube through the liquid inlet pipe 10. , solid and medicament enter the diversion cylinder after agitation and coagulation and the backflow of granular sludge. The area is set as a clarification zone 6, the top of the clarification zone 6 is provided with a liquid outlet pipe 11, the bottom is provided with a cone-shaped bottom plate 7, and the bottom central lower port of the bottom plate 7 is provided with the sludge thickening bucket 8 , and the mud scraper is provided above the periphery of the bottom plate 7, and the mud collecting and returning device 9 is provided below the bottom plate 7 at the same time.

In this embodiment, a sloping plate 13 is provided below the liquid outlet pipe 11 and located in the middle and upper part of the clarification zone 6 , and the sloping plate 13 is installed between the outer wall of the guide cylinder and the inner wall of the tank body 1 . The setting of the inclined plate 13 makes the clear liquid rise along the surface of the inclined plate 13. On the one hand, it is equivalent to setting an additional flow guiding device, which can reduce the disturbance and turbulence. On the other hand, it is equivalent to increasing the flow area to make the Marl is deposited on the surface of the inclined plate 13, which reduces the sedimentation distance and shortens the clarification time. The clarified clarified liquid is then discharged through the water collecting weir plate 12 and the liquid outlet pipe 11 .

In this embodiment, the mud scraper includes a reduction motor 14, a transmission shaft 15 and a scraper arm 16, and the scraper arm 16 is disposed above the bottom plate 7 at the bottom of the clarification zone. Since the bottom plate 7 is an inverted cone, the deceleration motor 14 drives the scraper arm 16 to operate, and the scraper arm 16 scrapes a part of the sludge on the bottom plate 7 into the sludge thickening hopper 8. The outlet is connected to the sewage pipe 17, and then the concentrated sludge is discharged out of the tank body 1 through the mud pump. On the other hand, the scraping arm 16 scrapes a part of the sludge on the bottom plate 7 into the sludge collecting and returning device 9, and the sludge collected in the sludge collecting and returning device 9 is lifted and returned to the double-layered sludge pump through the return outlet through its return outlet. The 2-stage reaction stirring coagulator is recycled, which changes the process condition of the conventional mechanical clarifier with low return sludge concentration, so that the return sludge quickly aggregates with liquid, solid and medicine to form large-particle agglomerates to accelerate sedimentation and achieve liquid-solid Efficient separation purposes.

In this embodiment, the guide tube can be set to a primary structure or a secondary structure. Wherein, the first-level guide tube is composed of a first-level guide tube 3 , and the upper end of the first-level guide tube 3 is fixedly connected to the top center of the tank body 1 . The secondary guide tube is composed of a grade I guide tube 3 and a grade II guide tube 4 . When the flow rate is fast, setting a diversion tube with a secondary structure can solve the problems of fast flow rate, uneven water distribution and serious turbulence of solid-containing wastewater entering the clarification zone, thereby achieving high-efficiency separation.

The working process of the device is as follows: add the medicament to the double-stage reaction stirring coagulator 2, rapidly stir and mix the reaction through the double-stage reaction stirring coagulator 2, and set the residence time for 3 to 5 minutes, so that the medicament and the solid-containing The wastewater is fully contacted and coagulated, and then enters the diversion cylinder through the liquid inlet pipe 10 (a controllable valve is provided on the liquid inlet pipe), and then falls to the diversion reflection device 5, and is distributed through the diversion reflection device 5. When the water enters the clarification zone 6, the flow rate of the fluid is set just so that the diversion and reflection device 5 can push the sewage/grey water to the edge of the clarification zone tank 1, so as to minimize the disturbance and turbulence caused by the water inflow. A sloping plate 13 is arranged above the clarification zone 6, so that the upward flow rises along the surface of the sloping plate 13. On the one hand, it is equivalent to setting an additional flow guiding device, which can reduce disturbance and turbulent flow, and on the other hand, it can increase the flow area The mud ash is deposited on the surface of the inclined plate 13 to reduce the sedimentation distance and shorten the clarification time. In addition, since the bottom plate 7 at the bottom of the clarification zone 6 is an inverted cone type, the deceleration motor 14 drives the scraper arm 16 to operate, and the scraper arm 16 scrapes a part of the sludge on the bottom plate 7 into the sludge thickening hopper 8, and the bottom of the sludge thickening hopper 8 A mud slag outlet is provided, and the mud slag outlet is connected to a mud discharge pipe 17, and then the concentrated mud slag is discharged out of the tank body 1 through a mud pump. At the same time, the scraper arm 16 scrapes a part of the sludge on the bottom plate 7 into the sludge collection and return device 9, and the sludge collected in the sludge collection and return device 9 passes through its return outlet and is then lifted and returned to the two-stage reaction stirring by the slurry pump. The coagulator 2 is recycled, which changes the process condition of the conventional mechanical clarifier with low concentration of return sludge, so that the return sludge quickly aggregates with liquid, solid and medicine to form large particle agglomerates to accelerate sedimentation and achieve high-efficiency separation of liquid and solid. Purpose.

Finally, it should be noted that although the above content has shown and described the embodiments of the present invention, it will be understood by those skilled in the art that these embodiments can be implemented without departing from the principle and spirit of the present invention. For various changes, modifications, substitutions and alterations, the scope of the present invention is defined by the appended claims and their equivalents.

The parts not involved in the present invention are the same as the prior art or can be implemented by using the prior art.

Claims (7)

1. A coupling separation device for removing SS (suspended solid) in catalytic cracking flue gas desulfurization wastewater, the device comprises a tank body, a two-stage reaction stirring coagulator, a guide flow cylinder, a guide flow reflection device, a mud scraper, a sludge concentration hopper and a sludge collection reflux device, wherein the two-stage reaction stirring coagulator is arranged at the outer side of the tank body, which is communicated with the guide shell through a liquid inlet pipe, liquid, solid and medicament enter the guide shell after being mixed and coagulated and returned to granular sludge, the guide flow reflection device is arranged below the guide flow cylinder, the guide flow cylinder and the area in the groove body around the guide flow reflection device are arranged as clarification areas, the top of the clarification zone is provided with a liquid outlet pipe, the bottom of the clarification zone is provided with a cone-shaped bottom plate, the lower port of the center of the bottom plate is provided with the sludge concentration hopper, and the mud scraper is arranged above the periphery of the bottom plate, and the mud collecting reflux device is arranged below the bottom plate.

2. The coupling separation device for removing the SS (suspended solid) in the catalytic cracking flue gas desulfurization wastewater according to claim 1, wherein an inclined plate for ascending and guiding the clarified liquid is arranged below the liquid outlet pipe and above the middle upper part of the clarification zone, and the inclined plate is arranged between the outer wall of the guide cylinder and the inner wall of the tank body.

3. The coupling and separating device for removing the SS wastewater generated by the catalytic cracking flue gas desulfurization according to claim 1, wherein the mud scraper comprises a speed reduction motor, a transmission shaft and a scraping arm, and the scraping arm is arranged above a bottom plate at the bottom of the clarification zone.

4. The coupling separation device for removing the SS from the catalytic cracking flue gas desulfurization wastewater according to claim 1, wherein the guide shell has a primary or secondary structure; the first-stage guide cylinder is composed of a first-stage guide cylinder, and the upper end of the first-stage guide cylinder is fixedly connected to the center of the top end of the groove body; the second-stage guide cylinder is composed of a first-stage guide cylinder and a second-stage guide cylinder, and the second-stage guide cylinder is sleeved on the periphery of the first-stage guide cylinder.

5. The coupling separation device for removing the SS (suspended solid) from the catalytic cracking flue gas desulfurization wastewater according to claim 1, wherein the sludge collecting reflux device is arranged at the center between the center of the bottom of the conical bottom plate and the outer wall of the tank body.

6. The coupling separation device for removing the SS from the catalytic cracking flue gas desulfurization wastewater according to claim 5, wherein the sludge collection reflux device is used for collecting the sludge with a heavier specific gravity at the bottom of the clarification zone, and the sludge collected in the sludge collection reflux device is lifted and refluxed to the two-stage reaction stirring and coagulating device through the reflux outlet thereof and the slurry pump so as to enhance the settling separation efficiency of the system.

7. The coupled separation device for removing the SS from the catalytic cracking flue gas desulfurization wastewater as recited in claim 1, wherein the sludge concentrating hopper is used for further concentrating the sludge with low specific gravity to increase the sludge concentration.

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