CA1075593A - Atmospheric cooling plant for cooling a potentially corrosive liquid containing substances capable of precipitation - Google Patents
Atmospheric cooling plant for cooling a potentially corrosive liquid containing substances capable of precipitationInfo
- Publication number
- CA1075593A CA1075593A CA243,220A CA243220A CA1075593A CA 1075593 A CA1075593 A CA 1075593A CA 243220 A CA243220 A CA 243220A CA 1075593 A CA1075593 A CA 1075593A
- Authority
- CA
- Canada
- Prior art keywords
- enclosure
- cooling
- liquid
- atmospheric
- cloths
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F28—HEAT EXCHANGE IN GENERAL
- F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
- F28F19/00—Preventing the formation of deposits or corrosion, e.g. by using filters or scrapers
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F28—HEAT EXCHANGE IN GENERAL
- F28C—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA COME INTO DIRECT CONTACT WITHOUT CHEMICAL INTERACTION
- F28C1/00—Direct-contact trickle coolers, e.g. cooling towers
- F28C1/04—Direct-contact trickle coolers, e.g. cooling towers with cross-current only
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F28—HEAT EXCHANGE IN GENERAL
- F28C—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA COME INTO DIRECT CONTACT WITHOUT CHEMICAL INTERACTION
- F28C3/00—Other direct-contact heat-exchange apparatus
- F28C3/06—Other direct-contact heat-exchange apparatus the heat-exchange media being a liquid and a gas or vapour
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B30/00—Energy efficient heating, ventilation or air conditioning [HVAC]
- Y02B30/70—Efficient control or regulation technologies, e.g. for control of refrigerant flow, motor or heating
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Vaporization, Distillation, Condensation, Sublimation, And Cold Traps (AREA)
- Physical Or Chemical Processes And Apparatus (AREA)
- Extraction Or Liquid Replacement (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
The invention concerns improvements to atmospheric cooling plants used for cooling corrosive liquids capable of pre-cipitating deposits on the walls. The walls are protected by smooth waterproof cloths made preferably of glass fibre-reinforc-ed polyester coated with polyvinyl chloride, the cloths are suspended from spars supporting the ceiling of the enclosure, and are constantly moved by the air blown into the enclosure, so that incrustations are detached and fall into the basin of cooled liquid. The invention allows cooling of such liquids with opti-mum efficiency without risk of corrosion or of accidents to personnel.
The invention concerns improvements to atmospheric cooling plants used for cooling corrosive liquids capable of pre-cipitating deposits on the walls. The walls are protected by smooth waterproof cloths made preferably of glass fibre-reinforc-ed polyester coated with polyvinyl chloride, the cloths are suspended from spars supporting the ceiling of the enclosure, and are constantly moved by the air blown into the enclosure, so that incrustations are detached and fall into the basin of cooled liquid. The invention allows cooling of such liquids with opti-mum efficiency without risk of corrosion or of accidents to personnel.
Description
me purpose of the inventlon is an atmospheric cooling plant, also called an atmospheric cooling tower~ used to cool a potentially corrosive liquid co~taining substances capable of precipitation.
Many processes for cooling solutions exist in industry~
and in the case of electrolysis, it is known to cool solutions by means of coils through the interior of which co~ water flows, said coils being su~merged in baths of electrolyte. However~ this type of cooling does not provide good efficiency, because it is indirect, and because the coils are rapidly covered by salts, further and considerably reducing the heat-transmis~ion; moreover, these coils take up too much space in the baths of electrolyte and have a poor resistance to corrosion.
An atmospheric cooling plant, on the other hand, is an installation in which a liquid, generally an aqUeo4s solution flows by gravity between the level where it is finely distributed and the level where it is collected, generally the water-level of a reservoir provided for this purpose~ During this journey, the liquid is in direct contact with a flow of atmospheric air; the overall relative movement of these phases is substantiallyeither counter-flow,or cross-flow~ although frequently both types of overall relative movements are provided, the air entering horizontally into the apparatus and emerging vertically, whereas the overall movement of the liquid is generally substantially vertical; in the cases when the liquid is finely distributed in the cooling fluid by nozzles projecting it upwards, there is, above the level of the nozzles,a ~ 107S593 portion of the contact which takes place in parallel-flow circumstances.
The atmospheric airflow is ~et in motion preferably by blower~, which blow external air into the body of the cooling plant, but thi~ may also be achieved by blowers which extract from the cooling system the air which has finished its contact with the liquid, ejecting it into the atmosphere where it may be removed by the natural draught of a chimney, or all known combinations of blowing and extracting fans, or by a chimney a~sisted by blowing or extracting fans.
Where there is nolri~k of the liquid forming serious deposits or incrustations, the thermal interchange between the liquid and the air takes place in exchange members generally made up of flat or corrugated plates or sheets, or various types of grid, over which the liquid runs and splashe~. On the other hand, when there is a ris~ that the liquid will form serious deposit~, and thus will rapidly clog the channels (orifices or passages) of the exchanger memhers, these latter may no longer be used. In these cases, the liquid is atomised by nozzles, and fills the interior space of the cooling plant in the form of a large number of droplets which are violently agitated by the airflow, and which con~tantly collide with one another until they fall into the reservoir.
During the thermal exchange between liquid and air, the air i~ heated, without, however, ever exceeding the temp-erature of the liquid at the input to the cooling system, and its humidity approache~ that with the same water-vapour pressure a~ the liquid to be cooled, without the relative humidity, however, ever being ab~ve lOO~o.
~075~93 As regards the liquid, generally an aqueous liquid, it cools; if it is heavily charged with dissolved substances~ or if these substances are not very soluble,~cooling brings the temperature below the precipitation threshold. Depending on the nature of the dissolved substance~ muds or flakes or even other types of precipita-tion may form.
In certain cases, which are particularly difficult, incrustations form, deposits adhering to all the rigid walls against which the supersaturated liquid comes in contact~ This is particularly notable during cooling of electrolytes in the zinc industry.
Such solutions are both extremely corrosive and lead to severe incrustation. Their pH, which is close to zero, due to the sulphuric ac1d (for example, 150 gm of H2S0~ per litre), necessitates the use of special materials such as stainiess steels and organic polymers (plastics) of suitable properties. As to the incrustations, they occur on the walls; these are in effect subject to the constant splashing of the solution. These deposi~s of gypsum rapidly grow~ by several centimetres per month , necessitating frequent, minute and difficult maintenance work, entailing immobi-lisation of the installation. Scaffolding must be periodically assembled inside the cooling plant, to permit the maintenance per-sonnel to remove the incrustations and drop them into the reservoir which has been emptied for this purpose. By the date of the bi-monthly maintenance, the incrustations have reached thicknesses of about 10 cm~ but blocks, saturated with acid , of a thickness of 15 cm are by no means rare. Any accidental falling of these represents grave danger during the maintenance work, and may often damage the walls of the cooling plant.
The conventional atmospheric cooling plant, particularly suitable for cooling a potentially corrosive liquid containing substances capable of precipitation, cQmpriSeS an enclosed space having on its upper portion means of causing a descent of the liquid in droplets, and at its lower portion a blower designed to blow between the lateral walls of the enclosure an atmospheric flow of air capable of cooling the liquid and causing eddies of air $n the enclosure, the cooled droplets and the precipitated solid matter being collected in a reservoir provided at the base of the enclosure.
According to the invention, the lateral walls of the enclosure are protected from the splashes of liquid and solid incrustations by smooth waterproof cloths whose lower edges are submerged in the reservoir, and which are suspended a slight distance in front of the walls, and are constantly moved by the eddies of air, thus detaching, during their formation, the deposited solids, which then fall into the reservoir.
Each cloth is suspended by any suitable means, such as hooks or cords wound around bars or tubes, and is stretched by any suitable mean5 of ballasting,such as sand or bars of lead~ the tension thus created being insufficient to immobilise the cloth, which would allow serious solid incrustations to form.
Cloths suitable for use with liquids containing mineral salts and acids, such as electrolyte during zinc refining, are preferably made of glass fibre-reinforced polyester with a coating of polyvinyl chloride.
The interior walls of the cooling plant are preferably hung with a single cloth made up of several smaller cloths welded together before assembly in the cooling plant.
-' ~0755C~3 A rapid and inexpensive method of cleaning the internal walls of an atmospheric cooling plant according to the invention, during the short ~tst ~ d~ periods of the ~ consists in removing the incrustations by manually shaking the cloths, this technique is of great advantage, as it is obvious that these cloths may thu~ be shaken much more energetically than could be achieved by eddies of air.
In accordance with one aspect of the present invention, there is provided an atmospheric cooling plant for cooling a potentially corrosive liquid containing substances capable of precipitation, formed by an enclosure having lateral walls and comprising on its upper portion means for causing the fall of the liquid in droplets, and in its lower portion a blower ~uitable for blowing in the body of the enclosure, i.e. between its lateral walls a current of atmospheric air capable of cool-ing the liquid and of creating movement of the air within the enclosure, the cooled droplets and precipitated solids being collected in a basin provided at the base of the enclosure, characterised in that the lateral walls of the enclosure are protected from splashes of liquid and incrustations of solid matter by waterproof smooth cloths which, their lower edge being submerged in the basin, are suspended a short distance in front of said walls, and are constantly moved by the movement of the air, thus detaching as they form, the deposited solids, causing them to drop into the basin.
In accordance with a further aspect of the present invention, there is provided a rapid and inexpensive method of cleaning the internal walls of an atmospheric cooling plant for cooling a potentially corrosive li~uid containing substances capable of precipitation, formed by an enclosure having lateral walls and comprising on its upper portion means for causing the fall of the liquid in droplets, and in its lower portion a blower suitable for blowing in the body of the enclosure, i.e. between ,~, its lateral walls a current of atmospheric air capable of - cooling the liquid and of creating movement of the air within the enclosure, the cooled droplets and precipitated solids being collected in a basin provided at the base of the enclosure, the lateral walls of the enclosure being protected from splashes of liquid and incrustations of solid matter by waterproof smooth cloths which, their lower edge being submerged in the basin, are suspended a short distance in front of said walls, and are constantly moved by the movement of the blown air, thus detaching as they form the deposited solids, causing them to drop into the basin, the method being carried out during short stopping periods of the blowing and characterised in that the incrustations are removed by manually shaXing the cloths.
The accompanying drawings show by way of example an embodiment of the invention.
Fig. 1 is a plan view of a conventional atmospheric cooling plant, whose internal walls are protected from splashes of liquid by an assembly of protective cloths suspended from the ceillng, Fig. 2 is a perspective view of the cooling plant in '' 20 Fig. 1, without the protective cloths, Fig. 3 shows on a larger scale one of the liquid-dis-tributing nozzles or jets mounted on the ceiling, Fig. 4 is an overall view of the assembly of the pro-tective cloths, and Figs. 5 and 6 show the assembly of the cloths respect-ively along section lines 5-5 and 6-6.
The cooling plant 10 (Fig. 1) is an enclosure of substantially parallelepipedic shape, whose small sides 11, llA
and large sides 12, 12A are made up of self-supporting panels 13, either flat (Fig. 2) or corrugated (Figs. 4 - 6), fixed to a concrete base 14, the panels are advantageously made of a high-quality polyester reinforced with glass fibre, and are reinforced ~6a-, either by vertical ribs 13A (Fig. 2), or by vertical spars 13B ( Figs . 4-6 ), supported by horizontal spars 13C .
~' '' ' -6b-107~593 The base is in the form of a rectangular basin 15 (Fig.1,2) intended to collect the corrosive liquid charged with precipltates after cooling of the latter. The basin is covered either with lead or anticorrosive brick, or also with a high-quality reinforced polyester. In addition, as corrosion is normally at its most intense at the liquid-air interface~ a hydraulic seal 16 (Fig.2) or flap is provided , made of the same polyester material, in order to ensure contact between the walls of the cooling plant and the basin.
One of the walls 11 (Fig.l), situated on one of the two small sides, has an inspection door 17, while the other, opposite wall llA~ contains a circular orifice 18 (Fig.2) into which is insert~d the edge of an annular guard or ferrule 19 of a blower fan 20. This latter~ which is mounted on the exterior of wall llA
on columns 21 of galvanised or painted steel~ has vanes 22 of polyester~ and a hub 23 of painted or galvanised cast metal~which is rotated by an electric motor 24 coupled to a reduction gearing 25; th3 external protective grille 26 for the fan is made of stainless steel of type 316.
The fan is also protected from falls of precipitate by a protective covering 27 of polyester which fits the orifice 18 on its upper portion~ and is then elongated ~ertically (Fig.l~
5, 6).
The atmospharic cooling plant is enclosed at the top by a ceiling made up of distinct layers 28 and 28A (Fig.2), of lamellar polyester, known as vesicular entrainment extractors, capable of capturing the drops of liquid while at the same time allowing the cooling air to be diffused to the exterior. These extractors , ~ f ~1'5 are supported by transverse profilcd column_ 29 and 29A with an H or T cross-section, and made of stainless steel of type 316, ~075593 the two terminal columns supporting each stage of extractors rèspectively 30 and 30A, which have a U cross-section.
A main duct, or hot-liquid cQllector 31, made of stainless steel of the same type, is mounted beneath the spars 30 in the longitudinal direction of the cooling plant, on either one side (Fig.2) or the other (Figs.1~ 5, 6) of the fan; it is connected by ties 32 to transverse secondary ducts 33, supported by spars 3 mounted parallel with the collector.
~ ach of the secondary ducts 33 is provided with several nozzles or ~ets 35 (Figs 2~3) ~ capable of emitting hot liquid 36 downwards.
Parts made of stainless steel or flat sheet 37 (Figs. 5,6) connect by means of welding the spars 29 to the collector 31~ in order to helps~po~lng it; plates 38 connect by means of weld~ng the spars 29 to spars 3~ with the purpose of supporting the secondary ducts 33.
For ease of assembly and maintenance of the installation7 the ends of the collector consist of sleeves 39, 39A with ties, which pass through the walls of the cooling plant (Figs.l~ 5 and Fig.2), one of the two being closed, and the other being supplied with liquid at high temperature, for example in the direction of arrow ~0 (Figs.l, 2, 5).
It is self-evident that the collector 31 and the lateral ducts 33 could also be made of a synthetic material such as polyvinyl chloride, reinforced if necessary by polyester, for example~ and in this case, of course~ the ducts would not be supported by welded plates.
The atmospheric cooling plant may be equipped with a ladder 41 (Fig.2 ), and a catwalk 42 (Figs.2 , 5) of protected steel.
In order to obtain the maximum degree of droplet cooling in a hot aqueous solution , the configùration and proportions of the enclosure, the dimensions and power of the blower fan, and the characteristics and output of the jet have all been carefully calculated; careful account has been taken not only of the initial temperature of the blown air and of the hot liquid, but also of other factors such as density, specific heat and vapour pressure of the liquid. For example, it was discovered that, when the electrolyte to be cooled is an aqueous solution of zinc sulphate, the total available surface for contact between the air and the droplets must be almost twice as great as that for the water of a conventional wet cooling tower.
Naturally, when the atmospheric cooling plant described above is used to cool sea water, brine, concentrated acid or alkaline aqueous solutions, etc.~ the steps taken to prevent corrosion may be sufficient (stainless steels and special polyesters~ conventional coverings, etc.)~ In the case of the hot electrolyte arising from zinc refining, on the other hand, as this contains about 200 g of ion sulphate per litre and 5~ of fluorine, and which precipitates on cooling gypsum saturated with sulphuric acid, the splashes of liquid attack the glass in the reinforced polyester, forming hYdrofluoric acid, and incrustations with all the risks and drawbacks enumerated above~
In order toprevent such a liquid coming into contact with the walls of the cooling plant, it is necessary to protect them. According to the invention, they are hung with smooth waterproof cloths made preferably of glass fibre reinforced 107559~3 polyester coated with polyvinyl chloride. These cloths~ before being freely suspended a short distance ~n front of the walls, are sewn together to form a continuous screen.
The walls 12 and 12A (Fig.l) of the cooling plant are concealed by cloths 43 and ~3A (Figs.l, 5, 6) whose upper edg~ is perforated in order to accommodate the lower leg of S-shaped hooks 4~ (Figs.4, 5, 6) , the upper leg being placed on bars or tubes ~5 fixed to the top of spars 29 with a T or H cross-section;
indeed , the ends of these spars are free of the lamellar extract~ layer 28 (Fig.2).
Each cloth ~3~ 43A (Figs.5, 6) is submerged beneath the surface 46 of the cooled liquid ~7 collected in basin 15, and the lower edge 48 of the cloth is provided on the interior with a ballasting material such as sand or lead, in order to prevent the flow of air blown in~o the enclosure from exposing the protected walls.
One cloth 49, seen in plan view (Fig.6) and in elevation (Fig.5) at the point of its seams connecting it to cloths ~3 and 43A, is placed in front of wall 11 so that the lower edge is submerged in the basin like the adjacent cloths; the upper edge is fitted with S-shaped hooks 50 , as are the other cloths, but the upper leg of the hooks rests on the upper part of the U-section spar 30.
A cloth 49a (Figs.l , 5, 6~ intended to cover wall ~, is suspended~ l1ke cloth 49, to the corresponding U-section spar 30, but the lower edge of the cloth is located just above the polyester protective element 27 of the blower (Figs.5, 6) and is fitted with ~075593 a ballast system 48A~ analogo~s to that of the adjacent cloths.
The part of the wall llA surrounding the blower need not be protected by the cloths, as the blown air blows the rain of droplets towards the interior of the enclosure.
When the atmospheric cooling plant is in operation, the continually renewed movement of air causes cooling of the droplets of liquid, coming from the jets, the cooled liquid dropping with the precipitate into the basin~ and the heated air leaves the enclosure through the ceiling of lamellar polyester~ any droplets carried along being captured by the latter. The splashes of liquid are stopped by the cloths~ and precipitate which might tend to form incrustations is constantly eliminated by the movements of the cloth due to the air in motion.
During the short stopping periods of the installation, the maintenance personnel vigorously shake the cloths by hand, thus detaching any precipitates which might still be adhering thereto.
Naturally, the invention is not limited to the embodiment which has been described and illustrated by way of example, and any modifications thereto would not go beyond its scope.
:.
: ~
.~ .
Many processes for cooling solutions exist in industry~
and in the case of electrolysis, it is known to cool solutions by means of coils through the interior of which co~ water flows, said coils being su~merged in baths of electrolyte. However~ this type of cooling does not provide good efficiency, because it is indirect, and because the coils are rapidly covered by salts, further and considerably reducing the heat-transmis~ion; moreover, these coils take up too much space in the baths of electrolyte and have a poor resistance to corrosion.
An atmospheric cooling plant, on the other hand, is an installation in which a liquid, generally an aqUeo4s solution flows by gravity between the level where it is finely distributed and the level where it is collected, generally the water-level of a reservoir provided for this purpose~ During this journey, the liquid is in direct contact with a flow of atmospheric air; the overall relative movement of these phases is substantiallyeither counter-flow,or cross-flow~ although frequently both types of overall relative movements are provided, the air entering horizontally into the apparatus and emerging vertically, whereas the overall movement of the liquid is generally substantially vertical; in the cases when the liquid is finely distributed in the cooling fluid by nozzles projecting it upwards, there is, above the level of the nozzles,a ~ 107S593 portion of the contact which takes place in parallel-flow circumstances.
The atmospheric airflow is ~et in motion preferably by blower~, which blow external air into the body of the cooling plant, but thi~ may also be achieved by blowers which extract from the cooling system the air which has finished its contact with the liquid, ejecting it into the atmosphere where it may be removed by the natural draught of a chimney, or all known combinations of blowing and extracting fans, or by a chimney a~sisted by blowing or extracting fans.
Where there is nolri~k of the liquid forming serious deposits or incrustations, the thermal interchange between the liquid and the air takes place in exchange members generally made up of flat or corrugated plates or sheets, or various types of grid, over which the liquid runs and splashe~. On the other hand, when there is a ris~ that the liquid will form serious deposit~, and thus will rapidly clog the channels (orifices or passages) of the exchanger memhers, these latter may no longer be used. In these cases, the liquid is atomised by nozzles, and fills the interior space of the cooling plant in the form of a large number of droplets which are violently agitated by the airflow, and which con~tantly collide with one another until they fall into the reservoir.
During the thermal exchange between liquid and air, the air i~ heated, without, however, ever exceeding the temp-erature of the liquid at the input to the cooling system, and its humidity approache~ that with the same water-vapour pressure a~ the liquid to be cooled, without the relative humidity, however, ever being ab~ve lOO~o.
~075~93 As regards the liquid, generally an aqueous liquid, it cools; if it is heavily charged with dissolved substances~ or if these substances are not very soluble,~cooling brings the temperature below the precipitation threshold. Depending on the nature of the dissolved substance~ muds or flakes or even other types of precipita-tion may form.
In certain cases, which are particularly difficult, incrustations form, deposits adhering to all the rigid walls against which the supersaturated liquid comes in contact~ This is particularly notable during cooling of electrolytes in the zinc industry.
Such solutions are both extremely corrosive and lead to severe incrustation. Their pH, which is close to zero, due to the sulphuric ac1d (for example, 150 gm of H2S0~ per litre), necessitates the use of special materials such as stainiess steels and organic polymers (plastics) of suitable properties. As to the incrustations, they occur on the walls; these are in effect subject to the constant splashing of the solution. These deposi~s of gypsum rapidly grow~ by several centimetres per month , necessitating frequent, minute and difficult maintenance work, entailing immobi-lisation of the installation. Scaffolding must be periodically assembled inside the cooling plant, to permit the maintenance per-sonnel to remove the incrustations and drop them into the reservoir which has been emptied for this purpose. By the date of the bi-monthly maintenance, the incrustations have reached thicknesses of about 10 cm~ but blocks, saturated with acid , of a thickness of 15 cm are by no means rare. Any accidental falling of these represents grave danger during the maintenance work, and may often damage the walls of the cooling plant.
The conventional atmospheric cooling plant, particularly suitable for cooling a potentially corrosive liquid containing substances capable of precipitation, cQmpriSeS an enclosed space having on its upper portion means of causing a descent of the liquid in droplets, and at its lower portion a blower designed to blow between the lateral walls of the enclosure an atmospheric flow of air capable of cooling the liquid and causing eddies of air $n the enclosure, the cooled droplets and the precipitated solid matter being collected in a reservoir provided at the base of the enclosure.
According to the invention, the lateral walls of the enclosure are protected from the splashes of liquid and solid incrustations by smooth waterproof cloths whose lower edges are submerged in the reservoir, and which are suspended a slight distance in front of the walls, and are constantly moved by the eddies of air, thus detaching, during their formation, the deposited solids, which then fall into the reservoir.
Each cloth is suspended by any suitable means, such as hooks or cords wound around bars or tubes, and is stretched by any suitable mean5 of ballasting,such as sand or bars of lead~ the tension thus created being insufficient to immobilise the cloth, which would allow serious solid incrustations to form.
Cloths suitable for use with liquids containing mineral salts and acids, such as electrolyte during zinc refining, are preferably made of glass fibre-reinforced polyester with a coating of polyvinyl chloride.
The interior walls of the cooling plant are preferably hung with a single cloth made up of several smaller cloths welded together before assembly in the cooling plant.
-' ~0755C~3 A rapid and inexpensive method of cleaning the internal walls of an atmospheric cooling plant according to the invention, during the short ~tst ~ d~ periods of the ~ consists in removing the incrustations by manually shaking the cloths, this technique is of great advantage, as it is obvious that these cloths may thu~ be shaken much more energetically than could be achieved by eddies of air.
In accordance with one aspect of the present invention, there is provided an atmospheric cooling plant for cooling a potentially corrosive liquid containing substances capable of precipitation, formed by an enclosure having lateral walls and comprising on its upper portion means for causing the fall of the liquid in droplets, and in its lower portion a blower ~uitable for blowing in the body of the enclosure, i.e. between its lateral walls a current of atmospheric air capable of cool-ing the liquid and of creating movement of the air within the enclosure, the cooled droplets and precipitated solids being collected in a basin provided at the base of the enclosure, characterised in that the lateral walls of the enclosure are protected from splashes of liquid and incrustations of solid matter by waterproof smooth cloths which, their lower edge being submerged in the basin, are suspended a short distance in front of said walls, and are constantly moved by the movement of the air, thus detaching as they form, the deposited solids, causing them to drop into the basin.
In accordance with a further aspect of the present invention, there is provided a rapid and inexpensive method of cleaning the internal walls of an atmospheric cooling plant for cooling a potentially corrosive li~uid containing substances capable of precipitation, formed by an enclosure having lateral walls and comprising on its upper portion means for causing the fall of the liquid in droplets, and in its lower portion a blower suitable for blowing in the body of the enclosure, i.e. between ,~, its lateral walls a current of atmospheric air capable of - cooling the liquid and of creating movement of the air within the enclosure, the cooled droplets and precipitated solids being collected in a basin provided at the base of the enclosure, the lateral walls of the enclosure being protected from splashes of liquid and incrustations of solid matter by waterproof smooth cloths which, their lower edge being submerged in the basin, are suspended a short distance in front of said walls, and are constantly moved by the movement of the blown air, thus detaching as they form the deposited solids, causing them to drop into the basin, the method being carried out during short stopping periods of the blowing and characterised in that the incrustations are removed by manually shaXing the cloths.
The accompanying drawings show by way of example an embodiment of the invention.
Fig. 1 is a plan view of a conventional atmospheric cooling plant, whose internal walls are protected from splashes of liquid by an assembly of protective cloths suspended from the ceillng, Fig. 2 is a perspective view of the cooling plant in '' 20 Fig. 1, without the protective cloths, Fig. 3 shows on a larger scale one of the liquid-dis-tributing nozzles or jets mounted on the ceiling, Fig. 4 is an overall view of the assembly of the pro-tective cloths, and Figs. 5 and 6 show the assembly of the cloths respect-ively along section lines 5-5 and 6-6.
The cooling plant 10 (Fig. 1) is an enclosure of substantially parallelepipedic shape, whose small sides 11, llA
and large sides 12, 12A are made up of self-supporting panels 13, either flat (Fig. 2) or corrugated (Figs. 4 - 6), fixed to a concrete base 14, the panels are advantageously made of a high-quality polyester reinforced with glass fibre, and are reinforced ~6a-, either by vertical ribs 13A (Fig. 2), or by vertical spars 13B ( Figs . 4-6 ), supported by horizontal spars 13C .
~' '' ' -6b-107~593 The base is in the form of a rectangular basin 15 (Fig.1,2) intended to collect the corrosive liquid charged with precipltates after cooling of the latter. The basin is covered either with lead or anticorrosive brick, or also with a high-quality reinforced polyester. In addition, as corrosion is normally at its most intense at the liquid-air interface~ a hydraulic seal 16 (Fig.2) or flap is provided , made of the same polyester material, in order to ensure contact between the walls of the cooling plant and the basin.
One of the walls 11 (Fig.l), situated on one of the two small sides, has an inspection door 17, while the other, opposite wall llA~ contains a circular orifice 18 (Fig.2) into which is insert~d the edge of an annular guard or ferrule 19 of a blower fan 20. This latter~ which is mounted on the exterior of wall llA
on columns 21 of galvanised or painted steel~ has vanes 22 of polyester~ and a hub 23 of painted or galvanised cast metal~which is rotated by an electric motor 24 coupled to a reduction gearing 25; th3 external protective grille 26 for the fan is made of stainless steel of type 316.
The fan is also protected from falls of precipitate by a protective covering 27 of polyester which fits the orifice 18 on its upper portion~ and is then elongated ~ertically (Fig.l~
5, 6).
The atmospharic cooling plant is enclosed at the top by a ceiling made up of distinct layers 28 and 28A (Fig.2), of lamellar polyester, known as vesicular entrainment extractors, capable of capturing the drops of liquid while at the same time allowing the cooling air to be diffused to the exterior. These extractors , ~ f ~1'5 are supported by transverse profilcd column_ 29 and 29A with an H or T cross-section, and made of stainless steel of type 316, ~075593 the two terminal columns supporting each stage of extractors rèspectively 30 and 30A, which have a U cross-section.
A main duct, or hot-liquid cQllector 31, made of stainless steel of the same type, is mounted beneath the spars 30 in the longitudinal direction of the cooling plant, on either one side (Fig.2) or the other (Figs.1~ 5, 6) of the fan; it is connected by ties 32 to transverse secondary ducts 33, supported by spars 3 mounted parallel with the collector.
~ ach of the secondary ducts 33 is provided with several nozzles or ~ets 35 (Figs 2~3) ~ capable of emitting hot liquid 36 downwards.
Parts made of stainless steel or flat sheet 37 (Figs. 5,6) connect by means of welding the spars 29 to the collector 31~ in order to helps~po~lng it; plates 38 connect by means of weld~ng the spars 29 to spars 3~ with the purpose of supporting the secondary ducts 33.
For ease of assembly and maintenance of the installation7 the ends of the collector consist of sleeves 39, 39A with ties, which pass through the walls of the cooling plant (Figs.l~ 5 and Fig.2), one of the two being closed, and the other being supplied with liquid at high temperature, for example in the direction of arrow ~0 (Figs.l, 2, 5).
It is self-evident that the collector 31 and the lateral ducts 33 could also be made of a synthetic material such as polyvinyl chloride, reinforced if necessary by polyester, for example~ and in this case, of course~ the ducts would not be supported by welded plates.
The atmospheric cooling plant may be equipped with a ladder 41 (Fig.2 ), and a catwalk 42 (Figs.2 , 5) of protected steel.
In order to obtain the maximum degree of droplet cooling in a hot aqueous solution , the configùration and proportions of the enclosure, the dimensions and power of the blower fan, and the characteristics and output of the jet have all been carefully calculated; careful account has been taken not only of the initial temperature of the blown air and of the hot liquid, but also of other factors such as density, specific heat and vapour pressure of the liquid. For example, it was discovered that, when the electrolyte to be cooled is an aqueous solution of zinc sulphate, the total available surface for contact between the air and the droplets must be almost twice as great as that for the water of a conventional wet cooling tower.
Naturally, when the atmospheric cooling plant described above is used to cool sea water, brine, concentrated acid or alkaline aqueous solutions, etc.~ the steps taken to prevent corrosion may be sufficient (stainless steels and special polyesters~ conventional coverings, etc.)~ In the case of the hot electrolyte arising from zinc refining, on the other hand, as this contains about 200 g of ion sulphate per litre and 5~ of fluorine, and which precipitates on cooling gypsum saturated with sulphuric acid, the splashes of liquid attack the glass in the reinforced polyester, forming hYdrofluoric acid, and incrustations with all the risks and drawbacks enumerated above~
In order toprevent such a liquid coming into contact with the walls of the cooling plant, it is necessary to protect them. According to the invention, they are hung with smooth waterproof cloths made preferably of glass fibre reinforced 107559~3 polyester coated with polyvinyl chloride. These cloths~ before being freely suspended a short distance ~n front of the walls, are sewn together to form a continuous screen.
The walls 12 and 12A (Fig.l) of the cooling plant are concealed by cloths 43 and ~3A (Figs.l, 5, 6) whose upper edg~ is perforated in order to accommodate the lower leg of S-shaped hooks 4~ (Figs.4, 5, 6) , the upper leg being placed on bars or tubes ~5 fixed to the top of spars 29 with a T or H cross-section;
indeed , the ends of these spars are free of the lamellar extract~ layer 28 (Fig.2).
Each cloth ~3~ 43A (Figs.5, 6) is submerged beneath the surface 46 of the cooled liquid ~7 collected in basin 15, and the lower edge 48 of the cloth is provided on the interior with a ballasting material such as sand or lead, in order to prevent the flow of air blown in~o the enclosure from exposing the protected walls.
One cloth 49, seen in plan view (Fig.6) and in elevation (Fig.5) at the point of its seams connecting it to cloths ~3 and 43A, is placed in front of wall 11 so that the lower edge is submerged in the basin like the adjacent cloths; the upper edge is fitted with S-shaped hooks 50 , as are the other cloths, but the upper leg of the hooks rests on the upper part of the U-section spar 30.
A cloth 49a (Figs.l , 5, 6~ intended to cover wall ~, is suspended~ l1ke cloth 49, to the corresponding U-section spar 30, but the lower edge of the cloth is located just above the polyester protective element 27 of the blower (Figs.5, 6) and is fitted with ~075593 a ballast system 48A~ analogo~s to that of the adjacent cloths.
The part of the wall llA surrounding the blower need not be protected by the cloths, as the blown air blows the rain of droplets towards the interior of the enclosure.
When the atmospheric cooling plant is in operation, the continually renewed movement of air causes cooling of the droplets of liquid, coming from the jets, the cooled liquid dropping with the precipitate into the basin~ and the heated air leaves the enclosure through the ceiling of lamellar polyester~ any droplets carried along being captured by the latter. The splashes of liquid are stopped by the cloths~ and precipitate which might tend to form incrustations is constantly eliminated by the movements of the cloth due to the air in motion.
During the short stopping periods of the installation, the maintenance personnel vigorously shake the cloths by hand, thus detaching any precipitates which might still be adhering thereto.
Naturally, the invention is not limited to the embodiment which has been described and illustrated by way of example, and any modifications thereto would not go beyond its scope.
:.
: ~
.~ .
Claims (5)
1. An atmospheric cooling plant for cooling a potentially corrosive liquid containing substances capable of precipitation, formed by an enclosure having lateral walls and comprising on its upper portion means for causing the fall of the liquid in droplets, and in its lower portion a blower suitable for blowing in the body of the enclosure, i.e. between its lateral walls a current of atmospheric air capable of cooling the liquid and of creating movement of the air within the enclosure, the cooled droplets and precipitated solids being collected in a basin provided at the base of the enclosure, characterised in that the lateral walls of the enclosure are protected from splashes of liquid and incrustations of solid matter by water-proof smooth cloths which, their lower edge being submerged in the basin, are suspended a short distance in front of said walls, and are constantly moved by the movement of the air, thus de-taching as they form the deposited solids, causing them to drop into the basin.
2. An atmospheric cooling plant according to Claim 1, characterised in that each cloth is suspended by any suitable means, such as hooks or cords wound around bars or tubes, and is tensioned by any suitable means of ballasting, such as sand or bars of lead, the tension thus created being insufficient to immobilise the cloth to such an extent as to cause serious in-crustations of solid matter.
3. An atmospheric cooling plant according to claim 1, characterised in that cloths suitable for liquids containing electrolytes like mineral salts and acids, such as the electrolyte from zinc refining, are made from glass fibre-reinforced polyester coated with polyvinyl chloride.
4. An atmospheric cooling plant according to Claim 1, characterised in that its internal walls are covered by a single cloth made up of several small cloths welded together before assembly in the cooling plant.
5. A rapid and inexpensive method of cleaning the internal walls of an atmospheric cooling plant for cooling a potentially corrosive liquid containing substances capable of precipitation, formed by an enclosure having lateral walls and comprising on its upper portion means for causing the fall of the liquid in droplets, and in its lower portion a blower suitable for blowing in the body of the disclosure, i.e. between its lateral walls a current of atmospheric air capable of cooling the liquid and of creating movement of the air within the enclosure, the cooled droplets and precipitated solids being collected in a basin pro-vided at the base of the enclosure, the lateral walls of the enclosure being protected from splashes of liquid and incrustations of solid matter by waterproof smooth cloths which, their lower edge being submerged in the basin, are suspended a short distance in front of said walls, and are constantly moved by the movement of the blown air, thus detaching as they form the deposited solids, causing them to drop into the basin, the method being carried out during short stopping periods of the blowing and characterised in that the incrustations are removed by manually shaking the cloths.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| BE155349A BE827863A (en) | 1975-04-11 | 1975-04-11 | ATMOSPHERIC REFRIGERANT FOR COOLING A POSSIBLY CORROSIVE LIQUID CONTAINING SUBSTANCES LIKELY TO PRECIPATE |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1075593A true CA1075593A (en) | 1980-04-15 |
Family
ID=3842759
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA243,220A Expired CA1075593A (en) | 1975-04-11 | 1976-01-08 | Atmospheric cooling plant for cooling a potentially corrosive liquid containing substances capable of precipitation |
Country Status (8)
| Country | Link |
|---|---|
| AT (1) | AT342096B (en) |
| CA (1) | CA1075593A (en) |
| DE (1) | DE2539053C2 (en) |
| ES (1) | ES444674A1 (en) |
| FR (1) | FR2307244A1 (en) |
| GR (1) | GR57857B (en) |
| IT (1) | IT1054263B (en) |
| NL (1) | NL178098C (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3630119C1 (en) * | 1986-09-04 | 1987-07-23 | Balcke Duerr Ag | Cooling tower for cooling a liquid containing solids |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE1820347U (en) * | 1960-06-18 | 1960-10-27 | Zentrax Ventilatoren Werk | DEVICE FOR RE-COOLING OF LIQUIDS. |
-
1975
- 1975-01-28 ES ES444674A patent/ES444674A1/en not_active Expired
- 1975-09-03 DE DE2539053A patent/DE2539053C2/en not_active Expired
- 1975-09-29 FR FR7529767A patent/FR2307244A1/en active Granted
- 1975-12-30 GR GR49698A patent/GR57857B/en unknown
-
1976
- 1976-01-08 CA CA243,220A patent/CA1075593A/en not_active Expired
- 1976-01-20 IT IT19410/76A patent/IT1054263B/en active
- 1976-02-05 NL NLAANVRAGE7601166,A patent/NL178098C/en not_active IP Right Cessation
- 1976-04-09 AT AT264176A patent/AT342096B/en not_active IP Right Cessation
Also Published As
| Publication number | Publication date |
|---|---|
| DE2539053A1 (en) | 1976-10-21 |
| NL178098B (en) | 1985-08-16 |
| ATA264176A (en) | 1977-07-15 |
| FR2307244A1 (en) | 1976-11-05 |
| IT1054263B (en) | 1981-11-10 |
| NL178098C (en) | 1986-01-16 |
| AT342096B (en) | 1978-03-10 |
| GR57857B (en) | 1977-07-05 |
| NL7601166A (en) | 1976-10-13 |
| ES444674A1 (en) | 1977-05-16 |
| FR2307244B1 (en) | 1980-04-25 |
| DE2539053C2 (en) | 1984-09-20 |
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