RU2505340C2 - Device for powder-gas cleaning and method of its regeneration - Google Patents

Abstract

FIELD: machine building.

SUBSTANCE: proposed device comprises casing with pipes, filter, swirler, precipitated impurities collection chamber, heater arranged at filter case, porous filtration elements arranged vertically inside the filter and having their top ends secured in tube plate arranged inside filter top part to separate powder-gas flow cleaning chamber from cleaned gas chamber. Swirler is arranged on filter cylindrical shell outer side, between said shell and casing. Device is regenerated by forcing high-pressure gas backflow through the filter. Said high-pressure flow is created by abrupt feed of gas contained at pressure in receiver through porous filtration elements into pre-evacuated working chambers of the filter. Note here that pressure inside said working chamber does not exceed barometric pressure.

EFFECT: efficient filtration, low drag, longer life.

4 dwg

Description

The inventive device for cleaning a dusty gas environment and a method for its regeneration can be used in chemical, food, pharmaceutical, microbiological, oil, gas, metallurgical, nuclear and other industries.

A device for cleaning gases from fine impurities according to the patent for the invention of the Russian Federation No. 2177821 (IPC class B01D 45/12, priority date 30.03.2001). This device consists of a housing with technological pipes, a collection chamber for deposited impurities and an exhaust chamber for gas, a vortex tube with a screw swirl and a hollow cylindrical displacer installed coaxially at its outlet, on the conical part of which screw cuts are made, and on the outer surface of the cylindrical part there are screw grooves communicating the cavity of the vortex tube with a chamber for collecting deposited impurities. At the same time, combined holes are made in the walls of the vortex tube and the cylindrical part of the displacer, combining the displacer cavity with the gas outlet chamber.

The disadvantages of this device are:

- the possibility of uncontrolled accumulation of sludge on the surface of the lower tube sheet due to the design feature of the tube itself, which is an obstacle to the free removal of filtered sludge into the collection chamber of the deposited impurities (the free space for the discharge of filtered sludge is limited by holes in the tube sheet) and, as a result, facilitates the formation of lower stagnant mud zones in this device;

- the inability to filter dust and gas environment with 100% humidity due to the lack of heating;

- a limited range of size and concentration of trapped mechanical particles of the pollutant in the dust and gas stream, which are correlated with the unregulated size (depth and width) of the screw slots of the screw swirler and cylindrical displacer located in the inner cavity of the filter element.

A device for gas purification according to the patent for the invention of the Russian Federation No. 2200616 (IPC class B01D 45/12, priority of 02/27/2002), which is closest in technical essence to the claimed technical solution and therefore selected as a prototype, is known.

This device comprises a housing with technological branch pipes, a coaxial filter element covering a vortex tube with a screw swirl, a collection chamber for deposited impurities, and an exhaust chamber for gas. According to the design of the device, the vortex tube is made of two components placed with a screw gap relative to each other, while the screw gap communicates the cavity of the vortex tube through a transfer pipe with a gas outlet chamber.

In this device, the gas stream passes through two stages of purification. An internal swirler is used as the first stage for preliminary separation of large dust particles, and as a second stage, the porous structure of the filter element located radially inside the casing of this device outside the swirl.

The disadvantages of this design of a device for cleaning gases from fine impurities are:

- the lack of direct heating of the filtered gas with 100% humidity with simultaneous centrifugal pre-treatment at the first stage, which complicates the subsequent final cleaning of the gas at the second stage of cleaning at its high humidity due to the high probability of filling the porous structure of the filter element with drop moisture (condensate), the consequence of which is a decrease in its bandwidth;

- insignificant, in comparison with the capacity of this device, the area of the working surface of the filter element, which leads to an increase in aerodynamic drag and a decrease in its resource;

- the possibility of uncontrolled accumulation of sediment on the surface of the lower tube sheet and, as a result, the formation of stagnant mud zones in this device due to the design features of the screen itself, which is an obstacle to the free removal of filtered sediment into the collection chamber of the deposited impurities (free space for discharge of filtered sediment limited by holes in the tube sheet);

The objective of the claimed device for cleaning dust and gas environment is:

- ensuring effective filtration of a gas stream with 100% humidity;

- increase the resource of the filter, which is part of the device for cleaning the dust and gas environment, before carrying out its regeneration;

- ensuring low aerodynamic resistance to gas flow;

- the exclusion of stagnant zones and ensuring the free removal of the filtered sediment.

The problem in the inventive device for cleaning the dust and gas environment is solved due to the fact that the device for cleaning the dust and gas environment, consisting of a housing with process pipes, a filter, a swirler, a chamber for collecting deposited impurities, according to the claimed technical solution further comprises a heater located on the filter housing, porous filter elements located in a vertical position in the inner cavity of the filter, the upper hollow ends of which are fixed in a tube sheet placed in a vertical hne part of the inner cavity of the filter and hermetically separating the cavity for cleaning the flow of dust and gas medium and the cavity of the purified gas, and the swirler is located on the outside of the cylindrical shell of the filter and is located between it and the housing.

Figure 1 presents a General view of a device for cleaning a dust and gas environment, figure 2 shows a section of the inner cavity of the filter of the inventive device, figure 3 is a cylindrical shell with screw guides of the swirler, figure 4 (view A) shows the location of the porous filter elements in the tube sheet.

The inventive device for cleaning a dust-gas medium (figure 1) consists of: a filter (1) for cleaning a dust-gas medium; a heater (2), for example a clamp heater, designed to heat the filtered dust and gas medium and the filter to a temperature above plus 100 ° C, located on the filter housing (3), which seals the filter working area from the environment; chambers for collecting precipitated impurities (4) used to collect filtered mechanical particles; a tangentially located inlet pipe (5) intended for the entrance of the cleaned gas stream; an outlet pipe (6) through which the purified gas exits; a pipe (7) connecting the filter (1) with the chamber for deposited impurities (4); receiver (8); an inlet pipe (9) intended for reverse pulse filter regeneration by high-pressure air flow; crane (10).

The filter (1), which is part of the inventive device for cleaning dust and gas environment, is shown in section in figure 2. It consists of: a tangentially located inlet pipe (5); outlet pipe (6); inlet pipe (9); filter housing (3); the heater located on it (2); a cylindrical shell (11) with screw guides located inside the filter housing (3) and forming between it and the filter housing (3) the cavity of the first stage (12) for cleaning the dust and gas mixture stream. In the inner cavity of the cylindrical shell (11), in its upper part, there is a tube sheet (13). The upper hollow ends of the porous filter elements (14), for example, cylindrical, are fixed in it. Porous filter elements (14) are in a vertical position in the inner cavity of the cylindrical shell (11) with an optimal radial lateral clearance with respect to each other. The outer surfaces of the porous filter elements (14) and the inner cavity of the cylindrical shell (11) form the inner working cavity (15) of the filter (1), which is intended for the second (finish) stage of gas flow purification.

Figure 3 shows a cylindrical shell (11) of the filter (1) with screw guides. On the surface of the cylindrical shell (11) there is a helical surface (16), designed to direct the flow of the incoming dust and gas mixture in a spiral from top to bottom in the cavity of the first stage of cleaning the dust and gas mixture flow (12).

Figure 4, in a view A, shows the attachment point of the porous filter elements in the tube sheet.

The upper hollow ends (17) of the porous filter elements (14) are made in the form of metal sleeves, have a hole and are tightly fixed in the tube sheet (13), due to which the cavities of the cleaned dust-gas stream (12 and 15) and the cavity of the purified gas are hermetically sealed ( 18) in the filter (1). The lower ends of the porous filter elements (14) are muffled.

The inventive device for cleaning a dust-gas environment works as follows. For cleaning, the dust and gas stream is fed through the inlet pipe (5) into the cavity of the first stage to clean the dust and gas mixture stream (12) of the filter (1), where it is forcibly twisted along the screw surface (16) between the filter housing 3 and the cylindrical shell 11 in the direction from top to bottom, after which dramatically changes its direction of motion to the opposite, i.e. upwards. Due to the influence of inertial and gravitational forces, a preliminary (rough) cleaning of the gas stream from large mechanical particles that fall out of the cleaned dust and gas medium and through the pipe (7) enter the collection chamber of the deposited impurities (4) takes place.

Simultaneously with cleaning at the first stage with a heater (2) located on the outer surface of the filter housing (3) (1), the dust and gas stream is heated to a temperature above + 100 ° С, which eliminates the formation of condensate when filtering the dust and gas stream with 100% humidity on the working surface of the porous filter elements (14) and, as a result, a decrease in the filter resource (1).

After the first cleaning stage, the gas stream is directed to the porous filter elements (14), for example, cylindrical, their upper hollow end (17) fixed in a vertical position in the tube sheet (13). Porous filter elements (14) occupy the inner working cavity (15) of the filter (1) as tightly as possible, which allows you to effectively develop a working filter surface and, as a result, minimize the aerodynamic drag of the filter (1). The pre-cleaned dust and gas stream passes the final (finish) filtration through the porous structure of the filter elements (14), after which the gas freed from fine mechanical particles through the holes in the upper hollow end of the porous filter elements (17), fixed in the tube sheet (13), enters the cavity of the purified gas (18) and is removed from the filter (1) through the outlet pipe (6). The tube sheet (13) is located in the upper part of the filter (1), which allows for the free removal of the filtered sludge into the collection chamber of the deposited impurities (4) from the porous filter elements (14) during filter regeneration, and also eliminates the appearance of stagnant zones during operation of the installation.

Preliminary cleaning of mechanical particles of a dusty gas environment with 100% humidity and its simultaneous heating in the first stage above plus 100 ° C reduces the mud load on the porous filter elements (14) during the final (finish) cleaning of the dusty gas environment, due to which aerodynamic drag and increase the permeability of porous filter elements (14), the filter resource (1) increases before their regeneration.

The effectiveness of the inventive installation for cleaning a dust and gas environment when cleaning air with 100% humidity and a flow rate of 38 m ³ / h of particles with a size of ≥0.3 μm is at least 99.9%. In this case, the pressure drop (aerodynamic drag) on the filter is not more than 0.5 kPa.

A method of regenerating a device for cleaning a dust and gas environment

A known method of filter regeneration according to the application for the invention "Bag filter with pulse regeneration for cleaning dusty gases", patent of the Russian Federation No. 2437710 (IPC class B01D 46/02, priority date 12.28.2009). The bag filter contains a cylindrical housing with a grill separating it into dusty and purified gas chambers, filter bags damped from below, a regenerating device, a conical dust collector with a shutter, purge pipes with an electromagnetic valve and a receiver, and also pipes for supplying dusty and purified gas outlets. The filter bags are tensioned on metal frames made in the form of spirals fixed to the grate, with the upper part of the sleeve fixed on the frame with a clamp and mounted coaxially in metal or polymer shells with an open bottom, in the upper part of which ejection nozzles in the form of truncated cones are placed.

The disadvantages of the proposed method of regeneration of the filter are:

- inefficient use of energy of the gas stream during the regeneration, because dust removal from the surface of the filter material of the sleeves is due to rarefaction arising in the free space between the shell and the filter sleeve due to the ejection of a gas stream when a jet of pressure air is supplied from the ejection nozzle (nozzle). The pressure drop arising in this case on the filter sleeve in the direction from the inside to the outside is much smaller than the differential that occurs when the flow is directly directed from the inside out;

- when regeneration is carried out in the filter housing, excessive pressure arises, which can reach significant values and may be unacceptable when using filters in metallurgical, vacuum or ventilation systems, especially in the chemical and nuclear industries, as well as in biotechnological industries and biohazardous facilities.

A device is known for filter regeneration according to the application for an invention “A method for regenerating a bag filter for cleaning high-temperature gases and a bag filter for its implementation”, application for invention of the Russian Federation No. 2005102321 (IPC class B01D 46/00, priority date 01/31/2005) , the closest in technical essence, in which regeneration is carried out by the method of acting on the filter elements in the direction from the inside out the blast wave emanating from the combustion products resulting from the ignition prepared with Mesi from combustible gas and air. The filter includes a vertical housing with a pyramidal bottom equipped with a nozzle for removing dust, filter elements, a partition for attaching them, a nozzle for removing purified gas, a nozzle for supplying a dusty gas stream to the apparatus, a cover with a connecting nozzle, and a regeneration system. The regeneration system consists of a device for preparing a combustible mixture of combustible gas and air, an explosive combustion chamber equipped with an electromagnetic valve, and turbulators located on the axes of the filter elements.

The disadvantages of this method are:

- the need for special combustible gas;

- when regeneration is carried out in the filter housing, excessive pressure arises, which can reach significant values and may be unacceptable when using filters in metallurgical, vacuum or ventilation systems, especially in the chemical and nuclear industries, as well as in biotechnological industries and biohazardous facilities.

The objective of the proposed method of regeneration of a device for cleaning a dusty gas environment is to regenerate the filter with a reverse high-speed gas stream without increasing the pressure inside its housing above atmospheric pressure, which eliminates the ingress of filtered sediment and harmful substances into the surrounding atmosphere.

This problem is solved due to the fact that the regeneration of the filter occurs due to the reverse high-pressure flow of gas, for example air, while according to the claimed method, this high-pressure flow is created due to the sharp supply of gas under pressure in the receiver through porous filter elements to previously evacuated working filter cavity, and in its working cavities there is no increase in pressure above atmospheric.

The inventive method of filter regeneration is implemented as follows: through the outlet pipe (6), the working cavities of the filter (1) [the cavity of the first stage of cleaning the dust and gas medium (12) and the internal working cavity (15)] and the collection chamber of the deposited impurities (4) are vacuumized pressure, for example, (30 ± 20) kPa, while the inlet pipe (5) and the inlet pipe (9) are closed. The receiver (8) is filled with gas, for example air, with an overpressure, for example, (70 ⁺¹⁰ ) kPa (the valve 10 is closed). When the valve (10) is suddenly opened, both the inlet pipe (9) and the air in the receiver (8) open up through the inlet pipe (9) due to the difference in absolute pressures, first into the cavity of the purified gas (18) and through the upper hollow ends the porous filter elements (17) passes inside the porous filter elements (14) and in a pulsed mode exits under high pressure through their porous structure (in the direction from the inside out). In this case, the mechanical particles filtered during the operation of the filter (1), overcoming the adhesion forces, are discharged from the porous filter elements (14) into the collection chamber of the deposited impurities (4), hermetically connected to the filter (1).

The volumes of the receiver (8), the working cavities of the filter (1) and the chamber for collecting the deposited impurities (4), as well as the air pressure in them, are calculated in such a way that during and after regeneration, the absolute pressure in the filter (1) does not exceed atmospheric pressure, which very important when filtering dangerous particles (for example, radioactive), the ingress of which into the atmosphere is unacceptable.

The technical result is an effective method of filter regeneration by a reverse high-speed gas flow, which is formed when a sharp increase in absolute pressure to 0.1 MPa in the working cavity of the filter under vacuum pressure without increasing pressure inside the filter housing.

Example

The absolute pressure in the filter after regeneration is determined by the formula:

P ₁ · (V ₁ + V ₂ ) + P ₂ · V ₃ = P ₃ · (V ₁ + V ₂ + V ₃ ), where:

P ₁ = 0.03 MPa — absolute pressure in the filter and in the dust collector before regeneration;

P ₂ = 0.17 MPa - absolute pressure in the receiver before regeneration;

P ₃ - the desired absolute pressure in the filter, in the dust collector and in the receiver after regeneration (MPa);

V ₁ = 76.8 l - the internal volume of the filter;

V ₂ = 116.6 l - the internal volume of the dust bag;

V ₃ = 134 l - the internal volume of the receiver.

The inventive device for cleaning a dust-gas mixture provides effective filtration of a gas stream with 100% humidity; increasing the resource of the filter, which is part of the installation for cleaning the dust and gas medium, before carrying out its regeneration; sufficiently low resistance due to the large working surface of the filtering elements; two-stage gas stream cleaning; compactness of the product as a result of the rational use of the volume of the internal cavity of the filter for cleaning the dust and gas environment and the final cleaning of dusty gas by filtering through the porous structure of the filter elements; simplicity in the manufacture of a filter for cleaning dust and gas environment and reliability in its operation.

The proposed method of regeneration provides the possibility of pulsed regeneration (with the removal of the filtered sediment outside the filter) of the porous filter elements by a reverse air flow without disassembling the inventive installation for cleaning dust and gas environment and without increasing above atmospheric internal pressure inside the filter housing, which eliminates the emission of harmful substances into the atmosphere, increases the productivity of its work and reduces the time for maintenance of the whole installation for cleaning the dust and gas environment.

Claims (2)

1. A device for cleaning a dust-gas medium, consisting of a housing with technological nozzles, a filter, a swirler, a chamber for collecting precipitated impurities, characterized in that it contains a heater located on the filter housing, porous filter elements located in a vertical position in the inner cavity of the filter, upper the hollow ends of which are fixed in a tube sheet located in the upper part of the inner cavity of the filter and hermetically separating the cavity for cleaning the flow of dust and gas medium and the cavity of the purified gas, and the vortex is located on the outside of the cylindrical shell of the filter and is located between it and the housing. 2. A method of regenerating a device for cleaning a dust-and-gas environment by supplying a high-pressure reverse gas flow through a filter, characterized in that the high-pressure flow is created by a sharp supply of gas under pressure in the receiver through porous filter elements into previously evacuated working cavities of the filter, in its working cavities there is no increase in pressure above atmospheric.

Images