RU2324517C1 - Film apparatus - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: apparatus with a body divided by horizontal partitions into chambers for liquid and gas entry and discharge. Contact pipes and distribution fittings are placed with a gap to the lower ends of the graded plates of gas-liquid distributors which are pressed to the surface of the lower horizontal partition of the chamber for gas entry. An additional horizontal partition forming a chamber for dispersed particles is mounted in the apparatus body; additional plates forming hermetic cavities with fittings for entry and discharge of the coolant are fixed to the plates of the gas-liquid distributor to allow removal of dispersed particles from the gas prior to its contact with the working liquid and thus to improve efficiency of mass exchange.

EFFECT: efficiency of mass exchange is increased, durability of the apparatus and working liquid is prolonged.

2 cl, 5 dwg

Description

The invention relates to apparatus for carrying out heat and mass transfer processes in a gas-liquid system, primarily for the purification of gases leaving bioreactors and other technological objects containing gaseous, solid and liquid trap components in the exhaust gas, and can be used in chemical, food and microbiological industry.

Known vortex apparatus for cleaning gases, including a cylindrical body with gas inlet and outlet nozzles, a tangentially vane gas swirl, a sprinkler in the form of a central perforated pipe equipped with a variable pitch screw, a hopper for collecting liquids and a nozzle for withdrawing liquids [SU No. 1346209, B01D 47/06, 1987, Bull. No. 39].

The specified apparatus does not have a sufficiently high liquid productivity and mass transfer efficiency due to weak mixing of the liquid and a slight holding capacity of the apparatus due to the absence of a helical spiral (roughness), which provides rotational-translational motion of the liquid film, causes centrifugal inertia and thereby increases the thickness of the film and provides its mixing in the troughs of roughness.

A device for cleaning exhaust gases from highly dispersed aerosols and absorption of harmful gaseous impurities, including a housing equipped with fittings, with nozzles and chambers located inside it with fixed swirlers and nozzles of a cylindrical-conical shape, which are made with a length equal to the length of the chamber [SU No. 860835, B01D 53/18, 47/10, 1981, bull. No. 33].

This device provides effective cleaning of particles and droplets with a size of 0.1-1.5 microns due to the condensation of liquid vapor, however, it does not have high mass transfer characteristics due to low liquid productivity (absorbent), high hydraulic resistance and metal consumption.

The closest in technical essence is a film apparatus containing a housing with technological fittings, divided by horizontal partitions into chambers for input and output of liquid and gas, contact tubes equipped with distribution pipes and screw spirals. Between the horizontal partitions forming the chamber for introducing gas coaxially with the contact pipes and the distribution pipes, gas-liquid distributors are installed, consisting of profiled plates placed tangentially to the distribution pipe with the formation of slots for gas passage, the upper ends of the plates are equipped with a plug fixed to the horizontal partition, and the lower ends of the plates are lowered into the annular gap formed by the inner surface of the contact tube and the outer surface of the distributor a connecting pipe, with adjacent plates provided with lateral ends with inserts that form, together with the plates, a channel for the passage of fluid, the cavity of which is in communication with the chamber for introducing fluid through openings made in the plug [RU No. 2260466, B01D 3/28, 53/18, B01J 10/02, 2005, bull. No. 26].

The specified apparatus has not a sufficiently high efficiency of mass transfer and capture of dispersed particles, an insignificant duration of use of the working fluid. Low mass transfer efficiency (gas solubility in the working fluid, absorbent) is due to the presence in the gas in contact with the liquid film of dispersed particles that suppress the turbulence of the gas stream, reduce the contact surface of the phases, and most importantly, get into the working fluid (when circulating the working fluid) , lead to a decrease in the equilibrium concentration of gas in the liquid and to an increase in its viscosity, which reduces the Reynolds number of the film and, consequently, its turbulence, which is directly related to the efficiency th mass transfer. The low capture efficiency of dispersed particles is due to the presence of one capture zone in the apparatus (in contact tubes), in addition, highly dispersed particles (less than 2 microns) are not captured in the apparatus due to their small size. The ingress of dispersed particles into the working fluid leads to a decrease in its operational characteristics and requires frequent replacement.

The invention solves the problem of increasing the efficiency of mass transfer and capture of dispersed particles, increasing the duration of the apparatus and the use of the working fluid due to the prevention of its contamination.

The technical result consists in increasing the efficiency of mass transfer, increasing the duration of the apparatus and the use of working fluid.

Prevention of contamination of the working fluid is carried out by removing dispersed particles and drops of moisture from the gas before contact with the working fluid. The formation of an additional capture zone for dispersed particles and droplets and particle enlargement due to condensation of moisture vapor in the gas on the particles increases the efficiency of mass transfer and capture, increases the operating time of the apparatus (since an uncontaminated liquid circulates in the apparatus) and the duration of use of the working fluid.

The specified technical result is achieved in that in a film apparatus containing a housing with technological fittings, divided by horizontal partitions into chambers for input and output of liquid and gas, contact tubes with distribution pipes and screw spirals, gas-liquid distributors made of profiled plates placed tangentially distribution pipes with the formation of slots for the passage of gas and equipped with plugs and channels for the passage of liquid, the cavity of which through the hole the cap is in communication with the fluid inlet chamber and the annular gap formed by the contact tube and the distribution pipe, according to the invention, the contact pipes and distribution pipes are placed with a gap L relative to the lower ends of the profiled plates of gas-liquid distributors, which are pressed against the surface of the lower horizontal partition of the gas inlet chamber, and an additional horizontal partition is installed in the housing, forming a chamber for dispersed particles, moreover, to the gas-liquid plates additional plates are attached to the distributor to form airtight cavities equipped with nozzles for entering and leaving the coolant.

The ratio of the outer diameter of the contact tube d to the gap value L is performed in the form of a ratio:

d / L≥2tgα,

Where

d is the outer diameter of the contact pipe,

L is the amount of clearance

α is the angle of the spray pattern.

The placement of contact tubes and distribution pipes with a gap relative to the lower ends of the profiled plates of gas-liquid distributors, which are pressed against the surface of the lower horizontal partition of the gas inlet chamber, as well as the installation of an additional horizontal partition in the casing of the apparatus with the formation of a chamber for dispersed particles, allow dispersed particles to be removed from the gas to its contact with the working fluid and thereby provide an increase in the efficiency of mass transfer and capture, continuously ti use the hydraulic fluid and of the apparatus.

The presence of a gap between the contact pipes, distribution pipes and the lower ends of the plates allows the dispersed particles to be discharged from the gas stream into the dispersed chamber due to the inertia acquired by the rotational-translational movement of gas (moving in slots for gas passage formed by profiled, tangentially mounted plates) particles. This forms an additional cleaning zone and prevents the dispersion of particles into the working fluid, which increases the efficiency of mass transfer and capture of dispersed particles, the duration of use of the working fluid and the operation of the apparatus. An increase in the efficiency of mass transfer (gas solubility in a liquid) is caused by an increase in the turbulence of the gas flow and the contact surface of the phases, with the exception of a decrease in phase turbulence and an equilibrium concentration of gas in the liquid due to a decrease in the dispersion of particles into the working fluid.

The increase in the efficiency of capture of dispersed particles is due to the presence of two capture zones in the apparatus (not only in contact tubes, but also in a chamber for dispersed particles), which allows for more complete gas purification. Due to the smaller penetration of dispersed particles into the working fluid, the operational characteristics of the working fluid and, consequently, its duration of use (work) are also improved. Pressing (tightly fitting) the lower ends of the profiled plates of gas-liquid distributors to the surface of the horizontal partition of the gas inlet chamber prevents gas from flowing through the lower ends of the plates and thereby ensures intensive rotational-translational movement of gas, a high value of inertia and, therefore, effective cleaning and increased efficiency mass transfer (it is well known that in a rotating stream of gas in contact with a liquid film, the mass transfer coefficients are higher).

The attachment of additional plates to the plates of the gas-liquid distributor with the formation of airtight cavities equipped with nozzles for introducing and discharging the coolant allows the coolant, for example, cold water, to be supplied to the surface of the plates, which allows gas cooling and, therefore, the condensation of moisture in the gas on the surface dispersed particles, carry out their enlargement and thereby realize the effective removal of small particles (less than 2 microns) from the gas stream. In this case, it is possible to increase the efficiency of mass transfer by reducing the temperature of the gas and liquid and increasing (according to Henry's law) the equilibrium concentration of dissolved gas.

The ratio of the outer diameter of the contact tube d to the value of the gap L is in the form

d / L≥2tgα,

which ensures the full opening of the torch of droplets (particles) moving in a rotating stream of gas exiting the channels, and thereby prevents them from falling into the cavity of the contact tubes.

For d / L <2tgα, part of the dispersed particles hits the inner surface of the contact tubes and is carried away with the gas, which is not permissible.

The above ratio can be obtained on the basis of the pattern of movement of the rotating torch of droplets with the opening angle of the spray torch a, shown in Fig. 5, according to which all the droplets in the spray torch will not fall into the inside of the contact pipe while observing the geometric ratio AC / CO≥tgα based on the fact that AC = d / 2, and CO = L, we have d / L≥2tgα.

Figure 1 shows a General view of the film apparatus; figure 2 - gas-liquid dispenser; figure 3 is a section of a gas-liquid distributor along section AA; figure 4 - in isometric connection of the main and additional plate in a gas-liquid distributor; figure 5 is a diagram of the disclosure of the torch droplets of a rotating gas stream.

The film apparatus consists of a casing 1, horizontal partitions 2, dividing the apparatus into chambers for introducing liquid 3 and gas 4 and a chamber for withdrawing gas and liquid 5. On the casing of the apparatus there are: a fitting for introducing a working fluid 6, a manhole - manhole 7, a fitting for introducing gas 8, liquid outlet 9 and gas outlet 10. Beneath the lower horizontal partition 2 with a gap L, contact tubes 11 are installed in which the distribution pipes 12 and a spiral spiral 13 are placed. Between the horizontal partitions 2, coaxially with the contact pipes 11 and the distribution patrons sides 12, installed gas-liquid distributors 14, consisting of plates 15 placed tangentially to the distribution pipe 12, with the formation of slots 16 for the passage of gas. The upper ends of the plates are equipped with a plug 17 mounted on the upper horizontal partition 2, and the lower ends of the plates are pressed against the lower horizontal partition 2 of the gas inlet chamber 4. In the plug 17 holes 18 are made in which the channels for the passage of fluid made of pipes 19 are fixed, the free end of which is lowered into the annular gap 20 formed by the contact pipe 11 and the distribution pipe 12. Below the horizontal partitions 2 there is an additional horizontal partition 21. The contact pipes 11 are fixed to them with the formation of the chamber 22 for dispersed particles. Additional plates 23 are attached to the plates 15 to form a sealed cavity 24 for the coolant. Each cavity 24 is equipped with nozzles for input 25 and output 26 of the coolant, which, respectively, are connected to the collectors for input 27 and output 28. The tightness of the cavities 24 is achieved by means of plates 29. A nozzle 30 is provided for withdrawing dispersed particles from the chamber 22.

The main design parameters of the device

The diameter of the contact pipes is 30-300 mm, the diameter of the distribution pipe is 25-240 mm, the length of the contact pipe is 0.1-6 m, the length of the distribution pipe is 0.1-0.2 m. The width of the annular gap formed by the contact pipe and the distribution pipe, 10 -50 mm, the width of the plates of a gas-liquid distributor 5-200 mm.

The film apparatus operates as follows.

The fluid through the nozzle 6 enters the chamber 3, and from there through the openings 18 in the plug 17 passes into the channels 19, fills the annular gap 20, and then flows down the inner surface of the contact tubes 11 in the form of a continuous fluid layer, performing a rotational-translational movement, intensively mixes, flowing around the coils of the helical spiral 13 and in contact with the gas.

Gas through the nozzle 8 enters the chamber 4, passes through the slots 16 formed by the plates, acquires a rotational-translational motion, contacts the surface of the plates 15 and 23, and is cooled by the input and output of cooling water (coolant) through the collectors 27, 28 and nozzles 25 , 26 in the cavity 24. As a result, moisture vapor is condensed on the dispersed particles in the gas stream and enlarged. At the exit from the ends of the plates, the dispersed particles (drops) due to the centrifugal force acquired by the rotational-translational motion of the gas, enter the chamber 22 and are discharged from the apparatus through the nozzle 30. The gas purified from dispersed particles enters the cavity of the distribution pipe 12, and then into the contact pipes 11 and is in contact with the liquid. The purified gas is discharged from the apparatus through the nozzle 10, and the liquid through the nozzle 9.

The use of the inventive film apparatus allows to increase the efficiency of mass transfer and capture, to increase the duration of the apparatus and the duration of use of the working fluid, which reduces the capital and current costs of the apparatus, and therefore, the cost of the manufactured product.

Claims (2)

1. The film apparatus, comprising a housing with technological fittings, divided by horizontal partitions into chambers for input and output of liquid and gas, contact tubes with distribution pipes and screw spirals, gas-liquid distributors made of profiled plates placed tangentially distribution pipes with the formation of slots for passage gas and equipped with plugs and channels for the passage of fluid, the cavity of which through the holes in the plug is in communication with the fluid inlet chamber and rings m a gap formed by the contact pipe and distribution pipe, characterized in that the contact pipes and distribution pipes are placed with a gap L relative to the lower ends of the profiled plates of gas-liquid distributors, which are pressed against the surface of the lower horizontal partition of the chamber for gas input, and an additional horizontal a partition forming a chamber for dispersed particles, with additional layers attached to the plates of the gas-liquid distributor us to form a sealed cavity, equipped with connections for coolant input and output. 2. The film apparatus according to claim 1, characterized in that the ratio of the outer diameter of the contact tube d to the gap value L is determined by the ratio d / L≥2tgα, where d is the outer diameter of the contact tube, L is the gap value, α is the angle of the spray pattern .

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