RU2379092C2 - Gas cleaner-drop catcher - Google Patents

Abstract

FIELD: production processes.

SUBSTANCE: invention refers to gas cleaning from hard particles by wet method and may be used in power industry for cleaning of boilers off gases. Device includes casing with antirust covering, tubes delivering and extracting gas, emulsifier, drop catcher designed as ring-shaped grid with radial blades and conic bottom and admission of hot air. Drop catcher is installed with circular clearance to gas cleaner covering, at that ends of drop catcher blades remote from center are shifted from their radial position in direction opposite to flow twist. Bottom of drop catcher is designed conic, top down with hole in cone top, at that inside conic bottom washing device is installed.

EFFECT: increase of degree of liquid separation from gas flows, decrease of reentrainment of liquid drops, simplicity of device production.

5 cl, 2 dwg

Description

The invention relates to the field of wet gas purification of particles from solid particles and can be used mainly in the energy sector for cleaning exhaust gases from boilers.

Known scrubbers droplet eliminators working with once-through venturi pipes. In this case, the main process of coagulation of aeolian particles and their capture by water droplets takes place in Venturi pipes (see, for example, “Guide to dust and ash collection”, Moscow, 1983, p. 120, Fig. 4.48), and the scrubber itself serves to capture drip entrainment and part of the ash deposited on its wall due to the centrifugal forces of the vortex gas flow in the scrubber (Fig. 4.36, ibid.). To flush these particles from above, a water film created by an irrigation belt flows down the walls lined with acid-resistant tiles.

Recently, vortex emulsifiers have been installed in scrubbers, which create an active zone for collecting ash particles in the foam layer. In this case, part of the barrel of the scrubber body is occupied by the emulsifier. The purified gases exit to the upper part of the scrubber with a high degree of saturation with small droplets and a low temperature (≈50 ° С) equal to or lower than the dew point temperature. Therefore, the question of precipitation of droplets, drainage of gas after the emulsifier becomes the most important. The removal of wet droplets into the flue behind the scrubber and into the smoke exhauster leads to a drift of the suction pockets of the smoke exhauster and the flue behind the exhaust fan, impaired traction and reduces the reliability of load bearing. The supply of hot air for heating gases does not solve the problem, and with a large kapleunos it greatly reduces the efficiency of the boiler installation, since it is necessary to emit heat with hot air outside the boiler. Therefore, the work of emulsifiers without droplet eliminators is almost impossible.

Currently, several drip eliminator designs have been developed. So, for example, according to patent No. 2225248, B 01D 53/86, 47/04, the droplet eliminator is made in the form of a tent made of corner elements. The tilt of the corners to the periphery ensures the removal of trapped drops on the wall of the scrubber and return to the working area of the emulsifier (prototype). The disadvantage of this droplet eliminator is its high resistance. In addition, the open grating of the droplet eliminator over its entire section allows intensive droplet removal in the center, where the ascending flows are the strongest.

To avoid this, other drip eliminator designs provide an annular variant of the droplet eliminator, where the gas flows along a ring with a lattice of blades arranged radially, providing additional twisting of the gases and the creation of centrifugal forces to separate the droplets on the scrubber wall, along which they flow into the active zone of ash collection below the droplet eliminator . In this case, a gap is provided between the shell of the droplet eliminator itself and the scrubber lining. Such a droplet eliminator is installed by the company "KOCH", for example, according to patent No. 2086293, class. 6 B01D 47/04, where it is not shown in the drawing, but is used in kind, and also according to patent 2163834, cl. B01D 47/04, according to which the KOCH company is currently introducing emulsifiers together with the annular droplet eliminators described above (we take them for prototypes). The design of the droplet eliminator according to patent No. 2158166 is similar.

The disadvantages of this prototype are:

1. Not enough complete capture of drops. This is due to the fact that the droplets do not have time to separate on the wall from the inside of a fairly wide annular flow and are outside the protective visor.

2. The bottom of the droplet eliminator, made in the form of a cone with its top up, contributes to the “removal” of droplets thrown from below from the bottom to the periphery of the bottom and their capture by an upward flow of gas in the annular part.

3. The provided rinsing of the droplet eliminator from above also increases drop entrainment, necessitates supplying more hot air for heating, which reduces profitability.

4. The droplets separated on the wall above the droplet eliminator, when draining down the smooth lining, experience counter-pressure of the rotating flow, which leads to re-capture of droplets from the wall surface.

5. In the annular gap between the shell of the drip eliminator and the scrubber lining there are no devices that prevent the leakage of gas flowing towards the drops.

Object of the invention

Increase the degree of separation of droplets from the gas stream.

To facilitate the conditions of their draining down the scrubber wall.

Do not allow droplets to enter the annular grid of the droplet eliminator, including from the liquid received for washing the droplet eliminator.

Do not allow gas to flow towards the flowing liquid in the annular gap.

This problem is solved as follows:

1. The droplet eliminator blades are deployed against the rotation of the spinning flow, i.e. the distal (from the center) end of the blade is offset circumferentially in the direction opposite to the flow twist. In this case, the velocity vector emerging from the intersection window section is deviated from the tangent circle to the outside, i.e. to the wall of the scrubber.

2. The bottom of the droplet eliminator is made cone with the top down and has acquired the shape of a plate. In this case, droplets sprayed onto its surface from the bottom flow down to the center and return to the emulsion layer.

3. The washing device installed inside the bottom plate is not affected by the upward vortex above the droplet eliminator; therefore, the washing water also flows into the emulsion layer through the hole provided at the top of the cone.

4. In the lining of the scrubber walls above the droplet eliminator, special vertical channels are made.

5. Below the annular gap, a special annular aerodynamic protrusion is made.

The proposed scrubber droplet eliminator is shown in the drawings, where in FIG. 1 shows a general view of a scrubber droplet eliminator; in FIG. 2 is a cross section of the inner lining with the channels and the installation of the droplet eliminator blades with a counter shift to the flow twist.

The scrubber body 1 (Fig. 1) with inlet 2 and outlet 3 nozzles contains an emulsifier 4 and a droplet eliminator 5. In the upper part, a nozzle 6 for supplying hot air is made. The lining of the inner part of the scrubber 1 at a height between the droplet eliminator 5 and the protective visor 7 is made with the presence of channels 8 (figure 2). An aerodynamic protrusion 10 is installed below the annular gap 9. The blades 11 of the drop eliminator 5 are installed at an angle to its plane, and their ends adjacent to the outer cylindrical shell 12 are offset against or along the rotation by a certain angle (they have a spiral deviation from the radius, Fig. 2 ) In the cone-shaped bottom 13 of the droplet eliminator, a water supply is provided through a sprayer 14 with a valve 15 on the inlet pipe.

In the lower part of the housing 1 is installed a water lock 16. Water is supplied to the emulsifier 4 by a pipe 17.

Scrubber droplet separator operates as follows.

Dusty gas through the inlet pipe 2 enters the body of the scrubber 1 and, passing sequentially emulsifier 4 and a droplet eliminator, enters the outlet pipe 3.

A foamy layer forms above the emulsifier 4, in which effective mass transfer and capture of solid particles by droplets of water flowing to the emulsifier through a pipe 17 occurs. In this case, portions of pulp flow down to the bottom of the scrubber 1 and are removed through the hydraulic lock 16. The gas escapes through the vanes 11 of the droplet eliminator 5 and receives additional twisting, so that the remaining small drops of water settle on it on the wall cladding of the housing 1 above the droplet eliminator. Encouraged by the high-speed gas flow, they move in a spiral along a smooth facing surface to the nearest channel 8, in which an aerodynamic shadow is created, which contributes to their rapid draining down into the annular gap 9, protected by an aerodynamic protrusion 10, which restricts the oncoming gas flow in the annular gap 9 from the bottom up. Due to this, all the separated droplets pass an annular gap 9 and again enter the space above the emulsifier 4. The displacement of the outer ends of the blades 11 in the direction of rotation of the gases (or against the direction of their radial position) provides for the concentration of the vortex to the wall when displaced against rotation and to the center when displaced in the direction of rotation. The length of the blade 11 is increased, and the outer shell 12 remains unchanged. With countercurrent displacement, a faster separation of the droplets onto the walls and drying of the gas stream after increasing its twist (flow) by the vanes 11 of the droplet eliminator 5 is achieved, therefore this particular displacement option is chosen. To flush ash deposits from the bottom of the bottom 13, a nozzle 14 with nozzles is provided, connected to a water source through an adjustable valve 15, which operates in a continuous or intermittent mode. The sprayer 14 is placed in the inner space of the conical bottom and is in the aerodynamic shadow, which eliminates the entrainment of droplets up during its operation. Deposits of ash that have arisen in the bottom of the bottom 13 or have fallen from above are washed off in this way with water, which is applied by the sprayer 14 to rotate in the bottom of the bottom with its removal through the drain hole at the top of the bottom 13 into the emulsifier zone 4. The main emulsifier is irrigated through the pipe 17 .

The gas purified from ash particles, having passed the droplet eliminator 5, does not have liquid droplets above the protective visor 7, but its temperature is very low and approaches or below the dew point temperature, which causes intense corrosion of the flues after the ash collectors. Therefore, through the pipe 6 serves hot air, which raises the temperature of the gases behind the ash collector, eliminating corrosion and deposits of ash behind the ash collector.

The proposed scrubber-droplet eliminator allows you to reduce or eliminate completely the removal of droplets above the protective peak 7. This achieves a significant increase in the temperature of the gases behind the ash collector after mixing them with hot air of the nozzle 6, which is unattainable with intensive removal of droplets and leads to an increase in heat loss with hot air through the nozzle 6 or increase corrosion of flues and chimneys.

The proposed droplet eliminator is simple in design and can be made of available material (stainless steel) in a short time.

Claims (5)

1. Scrubber droplet eliminator, comprising a housing with anti-corrosion lining, inlet and outlet gas pipes, as well as an emulsifier, droplet eliminator, made in the form of an annular lattice with radially spaced blades and a conical bottom, and a hot air supply, characterized in that the droplet eliminator is installed with an annular a gap to the scrubber lining, while the ends of the droplet eliminator blades distant from the center are offset from their radial position in the direction opposite to the flow swirl. 2. The scrubber droplet eliminator according to claim 1, characterized in that the bottom of the droplet eliminator is made with a cone with its top downward with an opening at the top of the cone. 3. The scrubber droplet eliminator according to claim 1 or 2, characterized in that a flushing device is installed inside the conical bottom of the droplet eliminator. 4. The scrubber droplet eliminator according to claim 1, characterized in that the vertical channels are made in the lining of the walls of the scrubber between the protective visor and the droplet eliminator. 5. The scrubber droplet eliminator according to claim 1, characterized in that an aerodynamic protrusion is made below the annular gap.

Images