CN113041759B - Multi-tube cyclone separator bottom flow gas-solid separation method and separation device - Google Patents

Abstract

The present invention provides a method and device for separating bottom flow gas and solid of a multi-tube cyclone separator, the method comprising dust-containing gas entering the multi-tube cyclone separator, separating dust particles from gas, and after separation, the dust particles and a part of gas enter a receiving bin from the bottom dust discharge port of the multi-tube cyclone separator, and the dust particles and gas entering the receiving bin constitute the bottom flow; the filter in the receiving bin separates the bottom flow and obtains purified gas; the purified gas is discharged after passing through a flow meter and a regulating valve. The present invention separates the bottom flow entering the receiving bin by a filter arranged in the receiving bin. Compared with the traditional method of arranging a cyclone separator and a critical nozzle after the receiving bin, the method can effectively ensure the efficient separation of bottom flow gas and solid and the long-term reliability of the equipment, avoid the safety hazard caused by the wear of the critical nozzle, and further improve the separation effect of the multi-tube cyclone separator by adjusting the gas flow entering the receiving bin.

Description

Multi-tube cyclone separator bottom flow gas-solid separation method and separation device

Technical Field

The invention relates to the technical field of petrochemical industry, and in particular to a multi-tube cyclone separator bottom flow gas-solid separation method and a separation device.

Background technique

Catalytic cracking is one of the most important secondary conversion processes of crude oil in refineries and is the main provider of domestic transportation fuels, gasoline and diesel, and petrochemical raw material propylene. At present, in order to reduce the energy consumption of the unit, catalytic cracking units are equipped with flue gas energy recovery systems, which mainly use flue gas turbines to convert part of the heat energy of the dust-containing gas generated in catalytic cracking into electrical energy.

In the related art, as shown in FIG1 , the dust-containing gas from the regenerator first enters a multi-tube cyclone separator 10 (hereinafter referred to as three cyclones) to separate the gas and dust particles of the dust-containing gas; after the separation operation, in order to ensure that the multi-tube cyclone separator 10 has a high dust removal efficiency, the dust outlet of the multi-tube cyclone separator 10 usually has a certain amount of gas leakage, so that a certain proportion of the gas falls into the receiving bin 20 along with the dust particles separated by the multi-tube cyclone separator, and the other part of the gas enters the flue gas turbine 50 to drive the impeller of the flue gas turbine to generate electricity, and then passes through the waste heat boiler, desulfurization and denitrification equipment in turn, and finally enters the chimney 130 and is discharged into the atmosphere. Among them, a certain proportion of gas and dust particles are collectively referred to as the bottom flow of the multi-tube cyclone separator. It should be understood that since a part of the gas entering the receiving bin is not lost, in the subsequent description, the part of the gas entering the receiving bin through the dust outlet of the multi-tube cyclone separator 10 is called the gas in the bottom flow.

In order to remove the dust particles contained in the underflow, it is necessary to successively set a fourth-stage cyclone separator (hereinafter referred to as the fourth cyclone) and a critical nozzle 40 after the receiving bin 20. The fourth cyclone is used to remove the dust particles contained in the underflow gas in the receiving bin 20. The underflow gas after separation is merged into the flue gas duct downstream of the flue gas turbine 50 through the critical nozzle 40, and is discharged into the atmosphere through the flue gas duct.

In addition, when the multi-tube cyclone separator 10 or the flue gas turbine 50 fails, the pipeline entering the flue gas turbine 50 can be closed, so that the dust-containing gas directly passes through a bypass with a pressure reduction orifice plate 60, and then enters the chimney through the waste heat boiler, desulfurization and denitrification equipment.

However, the above-mentioned process of separating the bottom flow of the multi-tube cyclone separator has the following defects: First, the particle size of the powder entering the four cyclones is small and easy to agglomerate, which causes the material legs of the four cyclones to be often blocked, and the powder separated by the four cyclones cannot be discharged smoothly, which leads to excessive dust content in the gas entering the critical nozzle. Since the flue gas velocity in the critical nozzle is very high, it is easy to cause the wear of the critical nozzle and the failure of the flow control function. In severe cases, it even causes accidents such as wear and leakage of the main flue gas pipeline, which seriously affects the safe production of the catalytic cracking unit. Second, when the main air volume of the regenerator fluctuates greatly due to fluctuations in the properties of the raw materials, changes in process parameters, adjustments to the processing plan, etc., the critical nozzle cannot adjust the flue gas flow rate, and it is impossible to ensure that the flow rate of the gas entering the receiving bin is always maintained at an optimized ratio of 2 to 8% of the dust-containing gas flow rate, that is, it is difficult to ensure the separation efficiency of the multi-tube cyclone. When the flue gas flow entering the receiving bin deviates from the ideal proportional coefficient, it is bound to cause the separation efficiency of the multi-tube cyclone to decrease, the flue gas turbine start-up cycle to shorten, and the total energy consumption of the catalytic cracking unit to increase.

In addition to the catalytic cracking unit in the refinery, some industrial fluidized bed reactors often use multi-tubular cyclone separators similar to those mentioned above, such as the methanol to olefins unit in the coal chemical plant. In the methanol to olefins unit, multi-tubular cyclone separators are installed outside the reactor and the regenerator, which are also referred to as three cyclones in the industry. The function of the reactor three cyclone is to further separate the particles carried in the reaction product gas, and the function of the regenerator three cyclone is the same as the three cyclones in the regenerator of the catalytic cracking unit. Due to the different physical properties of the gas medium and the difference in gas flow, at present, the reactor three cyclones and regenerator three cyclones of most methanol to olefins units are not equipped with flue gas turbines similar to those of catalytic cracking units.

However, no matter it is the reactor three-cyclone or the regenerator three-cyclone, in order to maintain the efficient operation of the three-cyclone, a certain proportion of gas needs to flow out from the dust exhaust port at the bottom of the three-cyclone, and this part of the gas also needs to be separated from the particles separated by the three-cyclone. If a receiving bin design similar to that of the catalytic cracking regenerator is adopted, that is, a fourth-stage cyclone separator is used to separate the gas and dust particles in this part of the bottom flow, it will also cause problems such as material leg bridging, material leg gas blowby, critical nozzle or other related pipeline wear, reduced three-cyclone separation efficiency, and poor ability to adapt to changes in the operating conditions of the device.

Summary of the invention

In the prior art, when a cyclone separator is used after a material receiving bin to separate gas and dust particles in the bottom flow entering the material receiving bin, the cyclone separator legs are prone to bridging or gas cross-flow, which can easily cause excessive dust content in the separated gas, easy wear of the critical nozzle, and thus reduce the separation performance of the multi-tube cyclone separator. The present invention provides a multi-tube cyclone separator bottom flow gas-solid separation method and separation device to solve many problems existing in the prior art.

In order to achieve the above-mentioned purpose, the embodiment of the present invention adopts the following technical solution:

An embodiment of the present invention provides a method for bottom flow gas-solid separation of a multi-tube cyclone separator, comprising: dust-containing gas enters the multi-tube cyclone separator to separate dust particles from gas.

The dust particles and a part of the gas collected after the separation operation enter the receiving bin from the bottom dust discharge port of the multi-tube cyclone separator, and the dust particles and gas entering the receiving bin constitute the bottom flow.

A filter is arranged in the material receiving bin, and the filter is used to separate the gas and dust particles in the underflow and obtain purified gas.

The purified gas leaving the filter is discharged after passing through a flow meter and a regulating valve, and the regulating valve is used to adjust the flow ratio of the gas entering the receiving bin and the dust-containing gas entering the inlet of the multi-tube cyclone separator.

The multi-tube cyclone separator underflow gas-solid separation method as described above, wherein a filter is arranged in the receiving bin, and the filter is used to separate the gas and dust particles in the underflow and obtain purified gas. Before this step, it also includes: pre-separating the gas and dust particles in the underflow by a pre-separator arranged in the receiving bin, after the pre-separator separates a part of the dust particles in the underflow, the unseparated dust particles and gas enter the filter again for further separation.

The multi-tubular cyclone separator bottom flow gas-solid separation method as described above, wherein the regulating valve is used to adjust the ratio of the gas entering the receiving bin to the dust-containing gas entering the inlet of the multi-tubular cyclone separator, and also includes: the regulating valve is used to adjust the flow rate of the purified gas obtained after passing through the filter according to the flow rate of the dust-containing gas entering the inlet of the multi-tubular cyclone separator, so that the flow rate ratio of the purified gas to the dust-containing gas is between 2% and 8%.

An embodiment of the present invention also provides a multi-tube cyclone separator underflow gas-solid separation device, comprising a multi-tube cyclone separator, a material receiving bin and a filter; the material receiving bin has a dust inlet, and the dust inlet is connected to the bottom dust exhaust port of the multi-tube cyclone separator; the filter is arranged in the material receiving bin, and the filter is used to filter the gas and dust particles in the underflow entering the material receiving bin; the gas outlet of the filter is connected to an exhaust pipe, and a flow meter and a regulating valve are provided on the exhaust pipe.

The multi-tube cyclone separator bottom flow gas-solid separation device as described above, wherein the receiving bin has an outlet; the filter includes a tube sheet, a filter head and a plurality of vertical filter tubes; the tube sheet is arranged on the outlet of the receiving bin, a plurality of the filter tube arrays are arranged below the tube sheet, the filter head is arranged above the tube sheet, and the filter head and the tube sheet enclose a purified gas chamber.

A plurality of back-blowing air ports are arranged in the purified gas chamber, each of which is connected to a filter tube. The back-blowing air ports back-blow the plurality of filter tubes one by one or in groups in sequence through a manual or automatic control program to clean the dust particles attached to the filter tubes.

As described above, the multi-tube cyclone separator underflow gas-solid separation device, wherein a pre-separator is also arranged in the receiving bin, and the inlet of the pre-separator is connected to the dust inlet, for pre-separating the gas and dust particles in the underflow to reduce the amount of dust particles carried in the gas entering the filter.

The multi-tube cyclone separator bottom flow gas-solid separation device as described above, wherein the pre-separator includes a shell, the shell has an air inlet channel, an air outlet channel and a dust exhaust duct, the air inlet channel is connected to the dust inlet, and the air outlet channel and the dust exhaust duct are both connected to the inner cavity of the receiving bin.

The multi-tube cyclone separator underflow gas-solid separation device as described above, wherein the pre-separator includes a support and a baffle assembly; the support is horizontally arranged on the inner wall of the collecting bin and is located between the dust inlet and the filter; the baffle assembly includes a plurality of baffles, and the plurality of baffles are installed on the support at intervals along an extension direction perpendicular to the dust inlet, and are located on the side of the support away from the filter; there are gaps between adjacent baffles; the baffles are used to collide with the gas and dust particles in the underflow, so that a part of the dust particles in the underflow are deposited to the bottom of the collecting bin along the surface of the baffle, and the gas in the underflow and the unseparated dust particles enter the filter through the gap for further separation.

In the multi-tube cyclone separator bottom flow gas-solid separation device as described above, the baffle assemblies are multiple groups, and the multiple groups of baffle assemblies are installed on the support at intervals along the extension direction parallel to the dust inlet; the gaps in adjacent baffle assemblies are staggered.

In the multi-tube cyclone separator bottom flow gas-solid separation device as described above, partitions are provided on both ends of the baffle along a direction perpendicular to the extension direction of the dust inlet, the partitions extend in a direction toward the dust inlet, and the partitions and the baffles have a preset angle.

The embodiments of the present invention provide a multi-tube cyclone separator bottom flow gas-solid separation method and separation device, the method comprising: dust-containing gas enters the multi-tube cyclone separator, dust particles and gas are separated, the dust particles and a part of gas collected after the separation operation enter a receiving bin from the bottom dust exhaust port of the multi-tube cyclone separator, the dust particles and the part of gas entering the receiving bin constitute the bottom flow; a filter is arranged in the receiving bin, the filter is used to separate the gas and dust particles in the bottom flow and obtain purified gas; the purified gas leaving the filter is discharged after passing through a flow meter and a regulating valve, the regulating valve is used to adjust the flow ratio of the gas entering the receiving bin and the dust-containing gas entering the inlet of the multi-tube cyclone separator. This embodiment separates the gas and dust particles entering the bottom flow through a filter arranged in the receiving bin. Compared with the traditional method of sequentially arranging a cyclone separator and a critical nozzle after the receiving bin, it can effectively ensure the efficient separation of gas and solid in the bottom flow of the multi-tube cyclone separator and the long-term reliability of the equipment, avoid the safety hazards caused by the wear of the critical nozzle, and at the same time, further improve the separation effect of the multi-tube cyclone separator by adjusting the flow ratio of the gas entering the receiving bin to the dust-containing gas in real time.

In addition to the technical problems solved by the embodiments of the present invention described above, the technical features that constitute the technical scheme, and the beneficial effects brought about by the technical features of the technical scheme, other technical problems that can be solved by the multi-tube cyclone separator underflow gas-solid separation method and separation device provided by the embodiments of the present invention, other technical features included in the technical scheme, and the beneficial effects brought about by these technical features will be further described in detail in the specific implementation methods.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present disclosure and, together with the description, serve to explain the principles of the present disclosure.

FIG1 is a schematic diagram of a process flow of an energy recovery system in an existing catalytic cracking system;

FIG2 is a schematic structural diagram of a multi-tube cyclone separator underflow gas-solid separation device provided in an embodiment of the present invention;

3 is a schematic structural diagram of another multi-tube cyclone separator underflow gas-solid separation device provided in an embodiment of the present invention;

Fig. 4 is a cross-sectional view taken along the direction A-A shown in Fig. 3;

FIG5 is a schematic diagram of the process flow of the present invention applied to the flue gas energy recovery system in catalytic cracking.

Description of reference numerals:

10: Multi-tube cyclone separator;

20: Material collection bin;

201: Export;

202: Dust inlet;

30: Cyclone separator;

40: critical nozzle;

50: Flue gas turbine;

60: pressure reducing orifice plate;

70: filter;

701: tube sheet;

702: filter tube;

703: filter head;

80: pre-separator;

801: air intake passage;

802: air outlet channel;

803: Dust exhaust duct;

804: Support member;

805: baffle;

806: partition;

807: gap;

90: flow meter;

100: regulating valve;

110: unloading tank;

120: valve;

130: Chimney.

Detailed ways

In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention.

In the absence of conflict, the embodiments of the present invention and the features described in the embodiments may be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

Taking the catalytic cracking unit in industry as an example, the process flow of the flue gas energy recovery system in the catalytic cracking unit in the prior art is described. As shown in FIG1 , the high-temperature flue gas from the regenerator first passes through the multi-tube cyclone separator 10 to remove most of the particles contained in the flue gas, and then the flue gas enters the flue gas turbine 50 to drive the impeller to generate electricity, and then enters the chimney 130 to be discharged into the atmosphere. A part of the flue gas enters the receiving bin 20 together with the dust particles separated by the multi-tube cyclone separator 10. After entering the receiving bin 20, this part of the gas passes through the cyclone separator 30 to remove the dust particles contained in this part of the gas, and then the purified gas passes through the critical nozzle 40 and then enters the main flue gas duct.

When the multi-tube cyclone separator 10 or the flue gas turbine 50 fails, the pipeline entering the flue gas turbine 50 can be closed, so that the high-temperature flue gas is directly discharged into the chimney 130 after passing through a bypass with a pressure-reducing orifice plate 60. Since two stages of cyclone separators connected in series are also arranged upstream of the multi-tube cyclone separator 10, the multi-tube cyclone separator 10 in the flue gas energy recovery system and the cyclone separator 30 for processing the underflow of the multi-tube cyclone separator can be referred to as three cyclones and four cyclones, respectively.

In actual industrial operation, the powder discharged by three-rotor separation is usually of small particle size and has high viscosity in high-temperature flue gas environment, so that the four-rotor legs often cannot discharge smoothly. When the legs are equipped with air-locking mechanisms such as wing valves, the four-rotor legs often have abnormal operation phenomena such as bridging; when no air-locking mechanism is set, the four-rotor legs often have gas blowby, and the separation efficiency is seriously reduced. In short, the separation effect of this design of four-rotor is often difficult to guarantee, so that the dust content of the gas entering the critical nozzle often exceeds the standard, which can easily cause critical nozzle wear and failure of flow control function. In severe cases, it may even cause accidents such as local wear and leakage of the main flue gas duct. In addition, industrial catalytic cracking units often experience large fluctuations in the main air volume of the regenerator due to fluctuations in raw material properties, changes in process parameters, adjustments to processing plans, etc., but the critical nozzle cannot adjust the flow of the underflow, and cannot always keep the gas flow entering the four-cyclone and the flue gas flow entering the multi-tube cyclone separator at an ideal ratio of 2 to 8%. When the flue gas flow entering the four-cyclone is too small or too large, it will inevitably cause problems such as a decrease in the three-cyclone separation performance, a shortened flue gas turbine start-up cycle, and an increase in the total energy consumption of the device.

Based on the above technical problems, an embodiment of the present invention provides a multi-tube cyclone separator bottom flow gas-solid separation method and separation device. This method no longer needs to set up a traditional cyclone separator and a critical nozzle after the material receiving bin. Instead, a filter is set at the top of the material receiving bin. Purified gas is obtained after filtration and discharged after passing through a flow meter and a regulating valve, which can improve the separation effect of the multi-tube cyclone separator.

Figure 2 is a schematic diagram of the structure of a multi-tube cyclone separator underflow gas-solid separation device provided in an embodiment of the present invention; Figure 3 is a schematic diagram of the structure of another multi-tube cyclone separator underflow gas-solid separation device provided in an embodiment of the present invention; Figure 4 is a cross-sectional view in the A-A direction shown in Figure 3; Figure 5 is a schematic diagram of the process flow of the present invention applied to the flue gas energy recovery system in catalytic cracking.

The following specific embodiments are all described in detail by taking the application of a multi-tube cyclone separator in a catalytic cracking unit as an example.

The multi-tube cyclone separator underflow separation method provided by the embodiment of the present invention comprises the following steps:

S101: The dust-containing gas enters the multi-tube cyclone separator 10 to separate the dust particles from the gas.

It is understandable that the dust-containing gas in this embodiment can be flue gas formed in the regenerator of a catalytic cracking unit or a regenerator of a methanol to olefins unit, or can be reaction product gas formed in the reactor of a methanol to olefins unit. Taking the catalytic cracking unit as an example, the dust particles are catalyst particles.

S102: The dust particles and a part of the gas collected after the separation operation enter the receiving bin 20 from the bottom dust outlet of the multi-tube cyclone separator 10, and the dust particles and gas entering the receiving bin 20 constitute an underflow.

In order to ensure that the multi-tube cyclone separator 10 has a high separation effect, a portion of the gas is usually required to enter the receiving bin 20 along with the dust particles from the bottom dust outlet of the multi-tube cyclone separator 10. The other portion of the gas enters the flue gas turbine 50 through the pipeline.

S103: A filter 70 is arranged in the receiving bin 20, and the filter 70 is used to separate the gas and dust particles in the underflow and obtain purified gas.

In order to avoid using a traditional cyclone separator to separate the gas and dust particles that fall into the bottom flow in the receiving bin 20, the present embodiment sets a filter 70 at the top of the receiving bin 20. The filter 70 can separate the gas and dust particles in the bottom flow to obtain purified gas. Accordingly, it also solves the technical problem in the traditional method that due to the poor discharge of the cyclone separator 30, the dust content of the gas in the critical nozzle 40 may exceed the standard, which may easily cause the critical nozzle 40 to wear and the flow control function to fail, and in severe cases even cause accidents such as local wear and leakage of the main flue gas duct.

In this embodiment, the filter 70 may be a multi-tube filter to quickly and effectively separate the gas and dust particles in the underflow.

S104 : The purified gas leaving the filter 70 is discharged after passing through the flow meter 90 and the regulating valve 100 . The regulating valve 100 is used to adjust the flow ratio of the gas entering the receiving bin 20 and the dust-containing gas entering the inlet of the multi-tube cyclone separator 10 .

Among them, the flow meter 90 is used to indicate the flow of purified gas, and the regulating valve 100 is used to control the flow of purified gas. The regulating valve 100 and the flow meter 90 can be linked with the flow meter used to display the dust-containing gas to adjust and control the ratio of the gas flow entering the receiving bin 20 and the dust-containing gas entering the inlet of the multi-tube cyclone separator 10 in real time, thereby ensuring that the multi-tube cyclone separator 10 can have the best gas leakage flow ratio and gas-solid separation effect under different gas processing volumes.

The bottom flow gas-solid separation method of the multi-tube cyclone separator 10 provided in this embodiment can be applied to all devices using a multi-tube cyclone separator to separate the gas and solid in the bottom flow of the multi-tube cyclone separator 10 and improve the separation efficiency of the multi-tube cyclone separator 10.

The embodiment of the present invention provides a method for separating gas and solid in the bottom flow of a multi-tube cyclone separator. Compared with the method of using a cyclone separator 30 to separate gas and dust particles falling into the bottom flow in a receiving bin 20 in the prior art, the embodiment of the present invention sets a filter 70 on the top of the receiving bin 20. The filter 70 can separate the gas and dust particles in the bottom flow to obtain purified gas, which can effectively ensure the efficient separation of gas and solid in the bottom flow of the multi-tube cyclone separator and the long-term reliability of the equipment, and avoid the safety hazards caused by the wear of the critical nozzle; and the purified gas passes through a flow meter 90 and a regulating valve 100, the flow meter 90 is used to indicate the flow rate of the purified gas, and the regulating valve 100 is used to control the flow rate of the purified gas. The regulating valve 100 and the flow meter 90 can realize linkage operation with the flow meter of the dust-containing gas entering the multi-tube cyclone separator 10, and adjust and control the proportional relationship between the gas flow entering the receiving bin 20 and the dust-containing gas entering the inlet of the multi-tube cyclone separator 10 in real time, thereby ensuring that the multi-tube cyclone separator 10 can have the best gas leakage flow ratio and gas-solid separation effect under different gas processing volumes.

On the basis of the above embodiment, a filter 70 is arranged in the receiving bin 20, and the filter 70 is used to separate the gas and dust particles in the underflow and obtain purified gas. Before this step, the following steps are also included:

The gas and dust particles in the bottom flow are pre-separated by the pre-separator 80 arranged in the receiving bin 20. The pre-separator 80 can separate a part of the dust particles, and the unseparated dust particles and gas enter the filter 70 for further separation. This step is recorded as S1021.

In order to reduce the load of the filter 70 in separating dust particles, before step S103, the gas and dust particles in the underflow can be pre-separated by a pre-separator 80 arranged in the receiving bin 20. By pre-separating some dust particles by the pre-separator 80, the content of dust particles entering the filter 70 is correspondingly reduced, thereby extending the service life of the filter 70.

The pre-separator 80 can be an inertial separator using the inertial separation principle or a separator using the centrifugal separation principle, such as a cyclone separator. The primary separator does not need to have a very high separation efficiency, but requires that the pressure drop cannot be too high, and is mainly used to reduce the processing load and backwash frequency of the filter 70, thereby extending the service life of the filter 70.

As an optional implementation of S104, the regulating valve 100 is used to adjust the flow rate of the purified gas obtained after passing through the filter 70 according to the dust-containing gas flow rate entering the inlet of the multi-tube cyclone separator 10, so that the flow rate ratio of the purified gas to the dust-containing gas is between 2% and 8%, so that the multi-tube cyclone separator 10 has an optimal air leakage flow ratio and dust particle separation effect under different dust-containing gas flow rates.

In actual operation, when the flow rate of the dust-containing gas entering the multi-tube cyclone separator changes, the staff can adjust the opening of the regulating valve 100 in real time according to the flow rate of the dust-containing gas and the actual flow rate of the purified gas displayed by the flow meter 90, so that the flow ratio of the purified gas to the dust-containing gas is between 2% and 8%, thereby ensuring that the multi-tube cyclone separator 10 has the best air leakage flow ratio and separation effect even under different main air total flow rates. The regulating valve can be adjusted manually by the staff or by using an automatic control system. When the regulating valve is adjusted by an automatic control system, the regulating valve can be a solenoid valve. When the dust-containing gas flow meter detects that the flow rate of the dust-containing gas has changed, the detection signal can be transmitted to the automatic control system, and the automatic control system issues an action command to adjust the opening of the solenoid valve.

As shown in Figure 2, an embodiment of the present invention also provides a multi-tube cyclone separator underflow separation device including a multi-tube cyclone separator 10, a material receiving bin 20 and a filter 70; the material receiving bin 20 has a dust inlet 202, and the dust inlet 202 is connected to the bottom dust exhaust port of the multi-tube cyclone separator 10; the filter 70 is arranged in the material receiving bin 20, and the filter 70 is used to filter the gas and dust particles in the underflow entering the material receiving bin 20; the gas outlet of the filter 70 is connected to an exhaust pipe, and the exhaust pipe is provided with a flow meter 90 and a regulating valve 100.

The multi-tube cyclone separator 10 can be connected to a regenerator in a catalytic cracking unit, or can be connected to a reactor or a regenerator in a methanol to olefins unit, and is used for gas-solid separation of dust-containing gas.

The multi-tube cyclone separator 10 may include a shell and a filter tube arranged in the shell, wherein the shell has a dust exhaust port, and the dust exhaust port can be connected to the receiving bin 20 through a connecting pipe to pass a portion of the gas and dust particles into the receiving bin 20. Taking the application of the multi-tube cyclone separator 10 in a catalytic cracking unit as an example, another portion of the gas separated by the multi-tube cyclone separator 10 enters the flue gas turbine 50 to drive the impeller of the flue gas turbine 50 to rotate and generate electricity.

The receiving bin 20 may include a bin body and a dust inlet 202 disposed on the bin body, wherein the dust inlet 202 may be connected to the dust outlet of the multi-tube cyclone separator 10, so that the multi-tube cyclone separator 10 separates dust particles and a portion of gas, i.e., bottom flow, which enters the receiving bin 20 through the dust inlet 202. In addition, the bin body may be a conical structure or a square structure.

A filter 70 is provided in the receiving bin 20, wherein the filter 70 can filter the gas and dust particles in the bottom flow entering the receiving bin 20 to achieve purification and separation of these gases and dust particles, and avoid the gas containing dust particles from being directly discharged into the air, which will cause environmental pollution and catalyst loss.

The gas outlet of the filter 70 is connected to an exhaust pipe, and the exhaust pipe can be directly connected to the atmosphere or connected to the atmosphere through a chimney 130, which is not specifically limited in this embodiment.

The exhaust pipe is provided with a flow meter 90 and a regulating valve 100, the flow meter 90 is used to display the flow rate of the purified gas discharged through the exhaust pipe, and the flow rate of the purified gas flowing through the exhaust pipe is controlled by the setting of the regulating valve 100. The flow meter 90 and the regulating valve 100 can be conventional products in the prior art, and will not be described in detail in this embodiment.

When the total main air flow of the regenerator in the catalytic cracking unit changes, the flow of the dust-containing gas entering the multi-tube cyclone separator 10 will change. The opening of the regulating valve 100 can be adjusted according to the actual flow of the pure gas displayed by the flow meter 90, so that the flow ratio of the purified gas to the dust-containing gas is between 2% and 8%, thereby ensuring that the multi-tube cyclone separator 10 has the best air leakage flow ratio and separation effect even under different total main air flow rates.

Start the filter 70. When a portion of the gas and dust particles enter the receiving bin 20, the filter 70 filters the gas and dust particles in the bottom flow entering the receiving bin 20. The filtered purified gas passes through the gas outlet of the filter 70 and enters the exhaust duct. The flow meter 90 and the regulating valve 100 arranged in the exhaust duct are used to adjust the flow of the purified gas in the exhaust duct.

An embodiment of the present invention provides a multi-tube cyclone separator 10 bottom flow gas-solid separation device, comprising a multi-tube cyclone separator 10, a material receiving bin 20 and a filter 70; the material receiving bin 20 has a dust inlet 202, and the dust inlet 202 is connected to the bottom dust exhaust port of the multi-tube cyclone separator 10; the filter 70 is arranged in the material receiving bin 20, and the filter 70 is used to filter the gas and dust particles in the bottom flow entering the material receiving bin 20; the gas outlet of the filter 70 is connected to an exhaust pipe, and the exhaust pipe is provided with a flow meter 90 and a regulating valve 100. The embodiment of the present invention filters the gas and dust particles entering the receiving bin 20 through the filter 70 arranged in the receiving bin 20. There is no need to adopt the traditional method of sequentially arranging four-rotor and critical nozzle 40 after the receiving bin 20 to separate the gas and dust particles entering the receiving bin 20, thereby avoiding the excessive dust content of the gas in the critical nozzle 40 due to the unsmooth discharge of the four-rotor legs, which in turn causes the critical nozzle 40 to wear and the flow control function to fail, and in severe cases even causes accidents such as local wear and leakage of the main flue gas duct.

In addition, the flow rate of the purified gas on the exhaust pipe can be displayed in real time by the flow meter 90, and the flow rate of the purified gas on the exhaust pipe can be adjusted by the regulating valve 100, so that the flow rate ratio of the purified gas to the dust-containing gas is between 2% and 8%, thereby preventing the flow rate of the gas entering the receiving bin 20 from being too large or too small, resulting in a decrease in the separation performance of the multi-tube cyclone separator 10, a shortening of the start-up period of the flue gas turbine 50, and an increase in the total energy consumption of the catalytic cracking unit.

As an optional embodiment of the filter 70, the material receiving bin 20 has an outlet 201; the filter 70 includes a tube sheet 701, a plurality of vertical filter tubes 702 and a filter head 703; the tube sheet 701 is arranged on the outlet 201, a plurality of filter tubes 702 are arranged in an array below the tube sheet 701, the filter head 703 is arranged above the tube sheet 701, and the filter head 703 and the tube sheet 701 enclose a purified gas chamber; a plurality of back-blowing air ports are arranged in the purified gas chamber, each of which is connected to a filter tube, that is, the number of back-blowing air ports is equal to the number of filter tubes, and the purified gas chamber is provided with back-blowing air ports corresponding to the plurality of filter tubes 702, each of which is connected to a filter tube, and the back-blowing air ports back-blow the plurality of filter tubes one by one or in groups in sequence through a manual or automatic control program to clean the dust particles attached to the filter tubes.

The tube sheet 701 can be fixed to the outlet 201 of the receiving bin 20 . It can be fixed to the outlet 201 of the receiving bin 20 by welding or bolting. In addition, the shape of the tube sheet 701 can match the shape of the outlet 201 of the receiving bin 20 .

Taking the orientation shown in FIG. 2 as an example, a filter tube 702 is provided below the tube sheet 701, and a filter head 703 is provided above the tube sheet 701. The tube sheet 701 and the filter head 703 enclose a purified gas chamber, wherein the outlet 201 can be provided on the filter head 703. In addition, a plurality of through holes arranged in an array can be provided on the tube sheet 701, and a filter tube 702 is fixedly provided on each through hole. The filter tube 702 can extend in a vertical direction to extend into the receiving bin 20, so that the purified gas separated by the filter tube 702 can enter the purified gas chamber through the through hole.

When the underflow enters the receiving bin 20, the gas in the underflow enters the interior of the filter tube 702 through the filter holes of the filter tube 702, while the dust particles are blocked and deposited on the outer wall of the filter tube 702 or in the receiving bin 20, thereby separating the gas and dust particles in the underflow.

After the filter 70 has been used for a long time, more and more dust particles will be deposited on the outer wall of the filter tube 702, and the filter tube 702 needs to be cleaned regularly and in time, otherwise the filtering effect of the filter 70 will be reduced. Therefore, back-blowing air ports corresponding to the multiple filter tubes 702 are provided in the purified gas chamber. In this embodiment, the opening and closing of the back-blowing air ports can be controlled by manual or automatic control programs to back-blow the multiple filter tubes 702 one by one or in groups in turn to clean the dust particles attached to the filter tubes 702.

Among them, the back-blowing air outlet can be connected to an external high-pressure airflow, and by introducing airflow into the filter tube 702, the dust particles attached to the filter tube 702 fall off into the receiving bin 20 under the action of the high-pressure airflow. In this embodiment, the filter tubes 702 can be back-blown one by one, or multiple filter tubes 702 can be divided into multiple groups, and only one group of filter tubes 702 or one filter tube 702 is back-blown each time to avoid excessive gas entering the receiving bin 20, resulting in excessive air pressure in the receiving bin 20, resulting in a reduction in the amount of bottom flow entering the receiving bin 20 through the dust exhaust port, thereby reducing the separation effect of the multi-tube cyclone separator. It can be understood that the order mentioned in this embodiment refers to back-blowing the filter tubes in a certain order.

In addition, in order to achieve independent control of each back-blowing air outlet, a valve can be set on each back-blowing air outlet, and the staff can selectively open one or more valves to back-blow the filter tube 702. Further, in order to achieve automatic control, a controller can also be set to control the opening and closing of the valve to achieve automatic control of the back-blowing air outlet.

As a feasible specific implementation method, a pre-separator 80 is also provided in the receiving bin 20 , and the inlet of the pre-separator 80 is connected to the dust inlet 202 , which is used to pre-separate the gas and dust particles in the underflow to reduce the amount of dust particles carried in the gas entering the filter 70 .

In order to reduce the workload of the filter 70, a pre-separator 80 can be set in the receiving bin 20. The pre-separator 80 can be used to perform a first treatment on the gas and dust particles in the underflow so that some dust particles are separated first. In this way, the dust particles entering the filter 70 will be reduced, thereby achieving the purpose of reducing the workload of the filter 70.

As an optional embodiment of the pre-separator 80, the pre-separator 80 includes a shell having an air inlet channel 801, an air outlet channel 802 and a dust exhaust duct 803, the air inlet channel 801 is connected to the dust inlet 202, and the air outlet channel 802 and the dust exhaust duct 803 are both connected to the inner cavity of the receiving bin 20.

Please refer to Figure 2, the gas and dust particles in the bottom flow enter the housing through the air inlet channel 801, and the gas and dust particles in the bottom flow form centrifugal force during the movement. The dust particles are heavy and the centrifugal force they are subjected to is also large. Therefore, the dust particles will fall directly into the receiving bin 20 along the dust exhaust pipe 803, and the lighter gas will be discharged into the receiving bin 20 through the air outlet pipe 802, and finally gathered at the filter 70. It can be understood that in this embodiment, the separation principle of the pre-separator 80 is the same as that of the cyclone separator.

As another optional embodiment of the pre-separator 80, the pre-separator 80 includes a support member 804 and a baffle assembly; the support member 804 is horizontally arranged on the inner wall of the receiving bin 20 and is located between the dust inlet 202 and the filter 70; the baffle assembly includes a plurality of baffles 805, and the plurality of baffles 805 are spaced apart on the support member 804 along an extension direction perpendicular to the dust inlet 202, and are located on the side of the support member 804 away from the filter 70; there is a gap 807 between adjacent baffles 805; the baffle 805 is used to collide with the gas and dust particles in the underflow, so that a part of the dust particles in the underflow are deposited to the bottom of the receiving bin 20 along the surface of the baffle, and the gas and unseparated dust particles in the underflow enter the filter 70 through the gap 807 for further separation.

Please refer to Figure 3. The pre-separator 80 provided in this embodiment adopts the principle of inertial separation to achieve the separation of dust particles. The pre-separator 80 may include a support member 804. The support member 804 serves as a carrier of the baffle assembly and can be fixed on the inner wall of the receiving bin 20. The support member 804 and the receiving bin 20 can be fixed in a welding or bolted manner, wherein the support member 804 is horizontally arranged on the inner wall of the receiving bin 20 to facilitate the installation of the baffle assembly. In addition, the support member 804 can be a plate-like body extending in a direction parallel to the dust inlet 202.

When the gas and dust particles in the bottom flow enter the receiving bin 20 from the dust inlet, they will first collide with the baffle assembly extending in the vertical direction. The baffle assembly intercepts the dust particles, causing some dust particles to move downward along the surface of the vertically arranged baffle assembly and fall directly into the receiving bin 20. Another part of the dust particles is intercepted and adsorbed on the outer surface of the filter tube 702 when passing through the filter tube 702 of the filter 70 with the gas, and accompanied by the continuous backblowing of the backblowing air outlet, these particles will fall into the receiving bin 20.

In order to enhance the separation effect of the pre-separator 80, the baffle assembly includes a plurality of baffles 805, which are spaced apart on the lower surface of the support member 804 along the extending direction perpendicular to the dust inlet 202, and there is a gap 807 between adjacent baffles. In this embodiment, the baffle assembly is designed to be composed of a plurality of baffles instead of using a whole plate with a larger area, so that the gas in the bottom flow can quickly flow to the filter 70 along the gap 807, thereby improving the separation efficiency of the filter 70.

In this embodiment, the extension direction perpendicular to the dust inlet is the direction of the arrow in Figure 4. In order to further enhance the separation effect of the pre-separator 80, please continue to refer to Figure 4. The baffle assemblies can be multiple groups, and the multiple groups of baffle assemblies are spaced apart on the support member 804 along the extension direction parallel to the dust inlet 202; the gaps 807 in adjacent baffle assemblies are staggered.

The gas and dust particles in the bottom flow first collide with the baffles in the first group of baffle assemblies near the dust inlet 202, so that some dust particles move downward along the surface of the vertically arranged baffles and fall directly into the receiving bin 20, and another part of the dust particles follow the gas through the gap 807 between adjacent baffles into the second group of baffle assemblies for a second pre-separation. After the second pre-separation, the dust particles and gas pass through the gap 807 in the second group of baffle assemblies and enter the third group of baffle assemblies for a third pre-separation. Finally, the unseparated dust particles and gas enter the filter 70 for final separation. In this embodiment, most of the dust particles are intercepted by multiple groups of baffle assemblies, thereby reducing the workload of the filter 70.

It is understandable that the number of baffle assemblies in this embodiment is not limited to the three groups described above, and can be freely selected according to actual conditions. In addition, the number of baffles in each group of baffle assemblies can also be freely designed, for example, the number of baffles in the first group of baffle assemblies can be three, the number of baffles in the second group of baffle assemblies can be four, and the number of baffles in the third group of baffle assemblies can be five.

Furthermore, partitions 806 are provided at both ends of the baffle plate in a direction perpendicular to the extension direction of the dust inlet 202, and the partitions 806 extend in a direction toward the dust inlet 202, and the partitions 806 and the baffle plate have a preset angle, preferably, the preset angle is 90 degrees, so that the baffle plate and the two partitions 806 form a U-shaped structure with an opening toward the dust inlet 202. By providing the partitions 806, the contact area and contact time of the baffle assembly with the gas and dust particles in the underflow can be increased, thereby increasing the separation effect of the pre-separator 80.

In order to facilitate unloading, a unloading tank 110 is provided at the bottom of the receiving bin 20, and a valve 120 is provided between the unloading tank 110 and the receiving bin 20, so that the particles can be continuously transferred from the receiving bin 20 to the unloading tank and then unloaded from the device.

As shown in Figure 5, the multi-tube cyclone underflow gas-solid separation device provided in this embodiment can be used in the flue gas energy recovery system in the catalytic cracking unit, including a multi-tube cyclone separator 10, the multi-tube cyclone separator 10 has a dust exhaust port and a separation gas outlet, wherein the separation gas outlet is connected to the flue gas turbine 50, and another part of the gas in the multi-tube cyclone separator can enter the flue gas turbine 50 through the separation gas outlet. The flue gas turbine 50 is used to convert part of the heat energy in the high-temperature flue gas purified by the multi-tube cyclone separator 10 into electrical energy, and the mouth of the flue gas turbine 50 is connected to the chimney 130.

The dust exhaust port of the multi-cyclone separator is connected to the receiving bin 20, the flow meter 90 and the regulating valve 100 in sequence, wherein a pre-separator 80 and a filter 70 are arranged in the receiving bin 20. After the gas and dust particles in the bottom flow are separated by the pre-separator 80 and the filter 70, the dust particles are deposited in the receiving bin 20, and the pure gas is passed into the chimney 130 through the exhaust pipe.

The separated gas outlet of the multi-tube cyclone separator 10 can also be connected in sequence to the pressure reducing orifice plate 60, the waste heat boiler, the desulfurization and denitrification equipment, etc. When the multi-tube cyclone separator 10 or the flue gas turbine 50 fails, the pipeline entering the flue gas turbine 50 can be closed, so that the high-temperature flue gas directly passes through a bypass with a pressure reducing orifice plate 60, and then enters the chimney 130 through the waste heat boiler, the desulfurization and denitrification equipment, etc.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims (6)

1. A method for separating bottom flow gas from solid in a multi-tube cyclone separator, comprising:

the dust-containing gas enters a multi-pipe cyclone separator to separate dust particles from the gas;

dust particles and a part of gas collected after the separation operation enter a receiving bin from a dust discharge port at the bottom of the multi-pipe cyclone separator, and the dust particles and the gas entering the receiving bin form underflow;

a filter is arranged in the receiving bin and is used for separating gas and dust particles in the underflow and obtaining purified gas;

The purified gas leaving the filter is discharged through a flowmeter and a regulating valve, and the regulating valve is used for regulating the flow ratio of the gas entering the material receiving bin to the dust-containing gas entering the inlet of the multi-pipe cyclone separator;

a filter is arranged in the receiving bin and is used for separating gas and dust particles in the underflow and obtaining purified gas, and the method further comprises the following steps:

The gas and dust particles in the bottom flow are pre-separated through a pre-separator arranged in a receiving bin, and after a part of dust particles in the bottom flow are separated by the pre-separator, the unseparated dust particles and the gas enter a filter for further separation;

The regulating valve is used for regulating the proportion of the gas entering the material receiving bin to the dust-containing gas entering the inlet of the multi-pipe cyclone separator, and the regulating valve further comprises: the regulating valve is used for regulating the flow of the purified gas obtained after passing through the filter according to the flow of the dust-containing gas entering the inlet of the multi-pipe cyclone separator, so that the flow ratio of the purified gas to the dust-containing gas is 2% -8%.

2. The underflow gas-solid separation device of the multi-pipe cyclone separator is characterized by comprising the multi-pipe cyclone separator, a receiving bin and a filter;

the receiving bin is provided with a dust inlet which is connected with a dust outlet at the bottom of the multi-pipe cyclone separator;

The filter is arranged in the receiving bin and is used for filtering gas and dust particles in the bottom flow entering the receiving bin;

the gas outlet of the filter is connected with an exhaust pipeline, and the exhaust pipeline is provided with a flowmeter and a regulating valve;

the material receiving bin is provided with an outlet; the filter comprises a tube plate, a filter head and a plurality of vertical filter tubes;

the tube plate is arranged on an outlet of the receiving bin, a plurality of filter tubes are arranged below the tube plate in an array manner, the filter end enclosure is arranged above the tube plate, and the filter end enclosure and the tube plate enclose a purified gas cavity;

A plurality of back-blowing air openings are arranged in the purifying gas chamber, each back-blowing air opening is communicated with one filter pipe, and the back-blowing air openings carry out back-blowing on the filter pipes sequentially one by one or group by group through a manual or automatic control program so as to clean dust particles attached to the filter pipes;

And a preseparator is further arranged in the receiving bin, and an inlet of the preseparator is connected with a dust inlet and is used for preseparating gas and dust particles in the underflow so as to reduce the quantity of the dust particles carried in the gas entering the filter.

3. The underflow gas-solid separation device of a multi-tube cyclone separator according to claim 2, wherein the preseparator comprises a housing having an inlet passage, an outlet passage and a dust exhaust duct, the inlet passage being connected to the dust inlet, the outlet passage and the dust exhaust duct both communicating with the interior chamber of the receiving bin.

4. A multi-tube cyclone underflow gas-solid separation apparatus according to claim 3 wherein the preseparator comprises a support and baffle assembly;

the supporting piece is horizontally arranged on the inner wall of the receiving bin and is positioned between the dust inlet and the filter;

The baffle assembly comprises a plurality of baffles which are arranged on the supporting piece at intervals along the extending direction perpendicular to the dust inlet and are positioned on the side surface of the supporting piece away from the filter;

Gaps are reserved between adjacent baffles; the baffle is used for colliding with gas and dust particles in the bottom flow so that part of the dust particles in the bottom flow are deposited to the bottom of the receiving bin along the surface of the baffle, and the gas and the unseparated dust particles in the bottom flow enter the filter through the gap for further separation.

5. The underflow gas-solid separation apparatus of a multi-tube cyclone of claim 4 wherein said baffle assemblies are in a plurality of groups, said plurality of groups being mounted on a support member at intervals along a direction parallel to the direction of extension of the dust inlet; gaps in adjacent baffle assemblies are arranged in a staggered manner.

6. The underflow gas-solid separation apparatus of a multi-tube cyclone as claimed in claim 4 or 5, wherein the baffle plates are provided with a baffle plate at both ends in a direction perpendicular to the direction in which the dust inlet extends, the baffle plate extends in a direction toward the dust inlet, and the baffle plate has a predetermined angle with the baffle plate.