RU133432U1 - GAS FLOW PARTICIPATOR - Google Patents

Abstract

The dispersed particle trap from the gas stream, including a separation chamber with a cowl axisymmetrically located inside it and devices for supplying and outputting a dust and gas stream, mounted on the ends of the chamber, characterized in that the cowling is made in the form of a cylinder, the length corresponding to the chamber length and diameter equal to 2 / 3 of the diameter of the separation chamber, with conical end ends having angles at the apex of the cone 45º, and the devices for feeding and outputting the dust and gas stream are equipped with a conical separation part for The main base of which, at an angle of 20 ° to the axis of symmetry of the separation chamber, is equipped with ultrasonic emitters in the form of bend-oscillating disks of stepwise variable thickness, mechanically and acoustically connected with piezoelectric transducers, reflectors made in the form of central cones with an opening angle of 90º and the diameter of the base equal to the diameter of the emitter, complemented by diverging cones with an inner diameter corresponding to the diameter of the emitter, the outer diameter, with tvetstvuyuschimi diameter of the larger base of the conical portion of the separation feed and output devices dust and gas flow, and an opening angle of 90º.

Description

The proposed technical solution is a utility model that relates to the field of separation of two-phase flows consisting of gas and solid dispersed particles.

Due to the need to capture harmful or valuable materials in the dispersed phase from the gas dispersion medium, there is a need to develop effective devices for the separation of small solid particles of various sizes (including nanoparticles) from the gas mixture stream. In this case, the traditional centrifugal and inertial aerosol capture devices are not effective.

A known dispersed particle trap from a gas stream comprising a housing with a tangential inlet nozzle, a vortex separation chamber formed by curved deposition surfaces separated by slotted outlets, an axially located purified gas outlet nozzle buried inside the housing and in communication with the tangential inlet nozzle through said slotted outlets, dust collecting hopper mounted in the lower part of the housing. In the wall of the vortex separation chamber there is a window communicating with the inlet pipe. The slotted terminals and the window are equipped with adjustable gates, and the angles between the radii passing through the centers of the window and the slotted terminals are 100-140 °. On the end wall of the vortex chamber, opposite to the outlet of the purified gas outlet and coaxially placed there is a shell with a diameter larger than the diameter of this nozzle and a width of 0.15-0.25 of the chamber width [1].

The main disadvantage of the known device is the low capture efficiency of nanodispersed dust fractions caused by intensive turbulence of the flow in the places of the slotted outlets and, as a consequence, the erosion of the concentrated dust layer, as well as the breakthrough of dust particles into the flow core between the shell and the outlet of the purified gas outlet. Moreover, the values of centripetal accelerations acting on the nanoparticles are not sufficient for the effective separation of the dust and gas stream.

The closest in technical essence to the proposed device is a trap of dispersed particles from a gas stream according to the patent [2], adopted as a prototype. The prototype contains a separation chamber with an axially symmetric radome located inside it, and devices for supplying and removing dust and gas flow mounted on the ends of the chamber.

An analysis of the capabilities of the device adopted for the prototype revealed the following significant disadvantages.

1. The four-blade flow swirl installed in the separation chamber does not significantly affect the direction of the dust and gas flow, as a result of which the tangential flow velocity is too low, as is the centripetal acceleration separating particles from the continuous continuous phase.

2. The small length of the fairing located at the outlet of the separation chamber, helps to straighten the swirling flow, reducing the efficiency of separation of dispersed particles from a continuous medium.

3. An annular channel of small cross section formed between the separation chamber and the cowling increases the hydraulic resistance of the apparatus.

4. The lack of separation efficiency due to the small centripetal acceleration acting on the nanoparticles, at the speed of the incoming stream, providing an acceptable hydraulic resistance of the apparatus.

All of these disadvantages cause low efficiency of capture of solid particles of the nanometer range.

The proposed technical solution is a utility model is aimed at eliminating the disadvantages of the prototype. The proposed catcher solves the problem of constructively improving the centrifugal horizontal cyclone and increasing its efficiency through the use of ultrasonic disk emitters, which are used as flexural-oscillating disks, mechanically and acoustically connected with piezoelectric transducers.

The essence of the technical solution lies in the fact that in the known catcher of dispersed particles from a gas stream containing a separation chamber with a cowl axisymmetrically located inside it, and devices for supplying and outputting a dust and gas stream mounted on the ends of the chamber, the cowling is made in the form of a cylinder, with a length corresponding to the length of the chamber and a diameter equal to 2/3 of the diameter of the separation chamber, with conical end ends having angles at the apex of the cone 45 degrees. The devices for supplying and outputting the dust and gas stream are equipped with a conical separation part, on the larger base of which, at an angle of 20 degrees to the axis of symmetry of the separation chamber, ultrasonic emitters are installed in the form of bend-oscillating disks of stepwise variable thickness mechanically and acoustically connected with piezoelectric transducers. Reflectors are installed on the back of the emitters, made in the form of central cones with an opening angle of 90 degrees and a base diameter equal to the diameter of the emitter, supplemented by diverging cones with an inner diameter corresponding to the diameter of the emitter, an outer diameter corresponding to the diameter of the larger base of the conical separation part of the feed devices and output dust and gas flow and an opening angle of 90 degrees.

The cowl mounted coaxially with the axis of symmetry of the separation chamber reduces the negative effect of the vortex core of the flow, contributing to a decrease in the curl of the flow and, accordingly, a greater deviation of the trajectories of solid particles in the direction of horizontal slots in the cylindrical tube of the separation chamber.

The conical separation part makes it possible to improve the conditions of the separation of the dust and gas stream due to the fact that dust deposition occurs during the continuous motion of the dust and gas stream with increasing speed along the smoothly decreasing radius of curvature, which contributes to the deep separation of the dust and gas mixture. The dust layer concentrated at the deposition surface is removed through an annular channel between the diffuser nozzle of the separation chamber and the side wall of the first hopper.

The dust and gas flow output device is equipped with a conical separation part and a tangential branch pipe to reduce hydraulic resistance.

A casing is installed outside the separation chamber, hermetically separated by three internal partitions, which form four isolated hoppers for collecting particles. Between the bunkers must be ensured tightness to prevent overflow of the gas stream and entrainment of trapped particles from the bunkers.

Three pairs of horizontal slots are made inside the separation chamber, radially spaced at an interval of 120 ° in the zone of the second and third hoppers, one pair of which is made in the upper part of the pipe, all the slots are made with frontal edges bent towards the gas flow. In the zone of the first hopper, horizontal slots are not made in the separation chambers, because they worsen the conditions of the twist of the stream, as a result of which the capture efficiency is not large.

The proposed design improves the capture efficiency of nanoparticles of particles up to 50%, but this efficiency is not enough for the practical application of the proposed apparatus.

To increase the efficiency of the process of separation of solid nanoparticles in centrifugal dust collectors, it is necessary to enlarge the nanoparticles under the action of high-intensity (more than 135 dB) ultrasonic vibrations (ultrasonic coagulation of aerosols) [3].

In the proposed device, increasing the efficiency of separation of nanoparticles in comparison with known devices is provided by the installation of two ultrasonic emitters. In this case, ultrasonic disk emitters act on particles by elastic vibrations propagated inside the technological volume along which the dust and gas stream moves. This leads to their mutual oscillations and unification [4]. Combining, agglomerates of particles increase their mass, as a result of which they are more easily separated by centripetal accelerations acting on them in the apparatus.

Ultrasonic emitters are made in a certain shape and arranged in such a way as to ensure uniform distribution of ultrasonic vibrations in the volume of the separation chamber with a sound pressure level of at least 135 dB, but not higher than a certain level, at which the process of dispersing particle agglomerates begins. The upper level of sound pressure depends on the properties and sizes of the separated particles.

The first disk emitter is located on the larger base of the dust and gas flow supply device at an angle of 20 degrees to the axis of symmetry of the separation chamber. The second disk emitter is mounted on a larger base of the dust and gas flow output device parallel to the first.

The emitters are made in the form of bending-oscillating disks of stepwise variable thickness, mechanically and acoustically connected with piezoelectric transducers. This design of the emitters allows you to radiate vibrations of each part of the disk in one phase, leading to a greater energy output, since the wave impedance of a flexurally oscillating emitter is better consistent with the wave impedance of the gas. Also, such a design of the emitter allows you to get a more uniform distribution of the amplitude of the oscillations on the surface of the emitter.

A piezoelectric transducer oscillating longitudinally along the acoustic axis, acoustically connected with a disk-shaped emitter performing bending vibrations, is powered by an ultrasonic electronic generator.

Reflectors are installed on the back of the emitters, made in the form of central cones with an opening angle of 90 degrees.

The diameter of the base of the central cones is equal to the diameter of the emitter, supplemented by diverging cones with an inner diameter corresponding to the diameter of the emitter, an external diameter corresponding to the diameter of the larger base of the conical separation part of the dust and gas supply and output devices and an opening angle of 90 degrees.

The use of reflectors of the described form ensures the formation of ultrasonic vibrations from two surfaces of the emitter

Thus, a uniform distribution of sound pressure inside the separation chamber is ensured, for effective coagulation.

The separation chamber allows to increase the residence time of solid particles in a centrifugal and ultrasonic field, thereby improving the efficiency of the coagulation process of particles and contributes to the separation of the dust-gas mixture, increasing the efficiency of their capture.

The essence of the proposed technical solution and the principle of its operation are illustrated in Fig.1-5.

Figure 1 presents a General view of the trap of dispersed particles from a gas stream;

figure 2 presents a longitudinal section of the proposed catcher of dispersed particles;

figure 3 presents a left view of the proposed trap dispersed particles;

figure 4 - section BB in figure 1 (the location of the horizontal slots with front edges bent towards the gas stream);

figure 5 presents the remote element A of figure 3.

The dispersed particle trap from the gas stream includes a separation chamber 1, a dust and gas stream supply device 2 with a conical separation part, on the larger base of which, at an angle of 20 degrees to the axis of symmetry of the separation chamber, a first ultrasonic emitter 5 is installed.

The separation chamber 1 is located horizontally, at the inlet of which a diffuser pipe 9 is installed, forming a first annular channel between the side wall of the first hopper. Outside the separation chamber 1, a casing 11 is installed, separated by three internal partitions 12, which form four insulated hoppers 13 for collecting particles.

Inside the separation chamber 1, there are three pairs of horizontal slots 14, radially spaced at 120 ° intervals in the zone of the second and third bins, one pair of which is made in the upper part of the pipe, all slots are made with frontal edges 15, bent towards the gas flow.

The cowl 4 installed in the center of the separation chamber 1 is made in the form of a cylinder with a length corresponding to the length of the chamber and a diameter equal to 2/3 of the diameter of the separation chamber 1, with conical end ends having angles at the apex of the cone of 45 degrees. It reduces the negative effect of the vortex core of the stream, contributing to a decrease in the curl of the stream and, accordingly, a greater deviation of the trajectories of solid particles in the direction of the horizontal slots 14 in the separation chamber 1.

The output device of the dust and gas stream 3 with a conical separation part is located coaxially with the separation chamber 1, on the larger base of which, at an angle of 20 degrees to the axis of symmetry of the separation chamber, a second ultrasonic emitter 6 is installed

In this case, the diffuser input 10 of the output device of the dust and gas stream 3 is built into the separation chamber 1 with the formation of a constant annular gap with the inner surface of the separation chamber.

Ultrasonic emitters 5 and 6 are made in the form of bending-oscillating disks of stepwise variable thickness, mechanically and acoustically connected with piezoelectric transducers. On the back of the emitters 5 and 6, reflectors are installed made in the form of central cones 8 with an opening angle of 90 degrees.

The diameter of the base of the central cones is equal to the diameter of the emitter 6, supplemented by diverging cones 7 with an inner diameter corresponding to the diameter of the emitter, an outer diameter corresponding to the diameter of the larger base of the conical separation part of the dust and gas flow supply and output devices and an opening angle of 90 degrees.

The catcher of dispersed particles from the gas stream operates as follows.

The separated dust and gas stream is fed through the inlet pipe into the dust and gas stream supply device 2, which forms a rotational movement of the dust and gas stream in it.

As a result of movement along a curved path under the action of centrifugal forces, it is stratified into a concentrated peripheral layer and a cleaned inner stream layer.

The dust layer concentrated at the inner surface of the separation part of the dust and gas stream supply device 2 is partially removed through the annular gap between the diffuser pipe 9 and the side wall of the first hopper.

The dusty gas stream passing through the diffuser pipe 9 enters the separation chamber 1, encountering the cowling 4. Solid particles, moving further along a spiral path under the action of centrifugal forces, are displaced to the inner surface of the separation chamber 1 and, encountering the front edges 15, are thrown through longitudinal horizontal slots 14 into insulated hoppers 13. Continuing the movement along a spiral path in the direction of the outlet of the purified gas outlet, particles in the dust and gas stream are squeezed to the inside It separation surface of the chamber 1 and moves in the annular gap formed by the diffuser inlet 10 and the inner surface of the separation chamber 1. The purified gas from particles unwinds smoothly removed from the dust collector through the gas stream output device 3.

Simultaneously with the supply of a dusty stream, an ultrasonic effect on suspended nanoparticles occurs. The coagulation process is carried out simultaneously by oscillations created by both sides of the disk emitters 5 and 6, and the oscillations created by the emitter side opposite to the particle flow are sent to it after reflection and passage of a distance exceeding the longitudinal size of the emitter by an amount multiple of half the wavelength of the emitted ultrasonic vibrations in in the air.

Thus, the uniformity of the ultrasonic effect over the entire diameter of the process volume from the emitting surface, which exceeds the area of the emitter itself, is ensured. By calculation, it was found that the location of the axis of the disk emitters 5 and 6 at an angle of 20 degrees to the horizontal axis of the separation chamber is optimal to achieve a uniform distribution of sound pressure level.

To determine the effectiveness of the proposed apparatus for trapping nanoparticles and establish the functionality of the created equipment, experimental studies were conducted. Based on experimental studies, it was found that the introduction of ultrasonic disk emitters into the design makes it possible to increase the capture efficiency of nanoparticles 30-50 nm in size from 50% to 98% due to the implementation of the coagulation process.

The sound pressure level of 135 dB is sufficient for coagulation of nanoparticles in the separation chamber at a calculated dusty gas flow rate of 500 m ³ / h, but should not exceed a certain level at which the dispersion of particle agglomerates begins.

Developed by Center for Ultrasonic Technologies LLC, the particle trap from the gas stream passed laboratory and technical tests, and was practically implemented in an existing installation. Small-scale production is scheduled to begin in 2013.

List of literature used in the preparation of the application

1. A.S. No. 1337121 of the USSR. Dust separator / Vasilevsky M.V., Anisimov Zh.A., Roslyak A.T., Zyatikov P.N .: publ. 09/15/87, Bull. Number 34.

2. Multistage centrifugal dust collector: US Pat. No. 2394629 Ros. Federation: IPC7 B01D 45/12 / Garkusha N.N., Tarasov V.P .; State educational institution of higher professional education “Altai State Technical University named after I.I. Polzunova ”(AltGTU) - No. 2009109654/15; declared 03/17/2009; publ. 07/20/2010.

3. Khmelev VN. Ultrasonic coagulation of aerosols (monograph) Barnaul: Altai State Technical University, 2010. - 235 p.

4. Shalunov A.V. Ultrasonic Oscillating System for Radiators of Gas Media [Text] / A.V. Shalunov, A. N. Lebedev, S.S. Khmelev, N.V. Kuchin, A. V. Shalunova // International Workshops and Tutorials on Electron Devices and Materials EDM'2008. - Novosibirsk: NSTU, 2008 .-- pp.226-271.

Claims (1)

The dispersed particle trap from the gas stream, including a separation chamber with a cowl axisymmetrically located inside it and devices for supplying and outputting a dust and gas stream, mounted on the ends of the chamber, characterized in that the cowling is made in the form of a cylinder, the length corresponding to the chamber length and diameter equal to 2 / 3 of the diameter of the separation chamber, with conical end ends having angles at the apex of the cone 45 °, and devices for supplying and outputting the dust and gas stream are equipped with a conical separation part for The main base of which, at an angle of 20 ° to the axis of symmetry of the separation chamber, is installed ultrasonic emitters in the form of bending-oscillating disks of stepwise variable thickness, mechanically and acoustically connected with piezoelectric transducers, reflectors made in the form of central cones with an opening angle of 90º and with a base diameter equal to the diameter of the emitter, supplemented by diverging cones with an inner diameter corresponding to the diameter of the emitter, the outer diameter, with tvetstvuyuschimi diameter of the larger base of the conical portion of the separation feed and output devices dust and gas flow, and an opening angle of 90º.

Images