DE3533328A1 - METHOD AND DEVICE FOR THE REMOVAL OF WATER STONE WITHOUT ACID TREATMENT - Google Patents

Description

KERIPAR, Budapest / Hungary

METHOD AND DEVICE FOR REMOVING HYDROSTONE COATINGS WITHOUT ACID TREATMENT

The invention relates to a method and a device for removing water scale coatings without the use of a mineral acid, e.g. metal surfaces coated with water scale.

It is known that the mineral scale deposition severe problems of the device caused mainly on heat transfer surfaces, for example ₀ in boilers, scouring Vind Siedeanlagen and heat exchange due to reduction of the Wärmeübertragungsieistung, increasing the flow resistance of various other disorders, possibly malfunction. Many technical solutions are known to counteract the harmful effects of scale deposits. These solutions can be divided into two parts: one part of the technical solution is used to prevent the formation of scale, the other to remove the existing scale coating.

The known solutions mostly consist of softening the water. This can be done by chemical Precipitation of calcium, izium and magnesium salts and pilgrimage of the precipitate formed, "after which the alkali metal ions are exchanged for sodium ions will. Exchange electrolytes can also be used. The application of water softening is limited not only by the cost of the process, but also by the fact that the electrolyte content of the water in the interest of its intended use possibly by official regulations is regulated. So can the drinking water, the domestic hot water for reasons of health protection not be electrolyte-free, although the chemical composition

: is ^optimal: not physiologically often reduction of drinking water. ■;

Purely to prevent the formation of water scale - and also ^{for the} subsequent loosening of the existing water scale - the magnetic treatment of the water is proposed, after which the water is guided through a magnetic field before being fed into the object to be protected. Many positive and negative experiences with this method are described in the literature (e.g. Szakäll-Nyilassy: Hidrologiai Közlöny 1965 (10) 477-48.0). No literature has yet been found for the assumed - as yet hardly proven - mechanism of action of the method, but a major practical difficulty lies in the fact that the reproducibility of this solution is problematic according to the literature and practical experience.

For subsequent, mostly temporary Mechanical and chemical methods are known to remove the scale coating. With the mechanical Various grinding and abrasive agents are used used, in the chemical solution the water scale (generally in hydrochloric acid, as mineral acid) solved. Both procedures are difficult and can be applied to a limited extent. Next to it is the protection of the metal parts in the acidic treatment, not soothingly resolved even by the use of inhibitors, and what's more Work, health and environmental problems come.

Because of the disadvantages described above, there was a need for the inventive method and the To develop devices based on the knowledge that the setting of the well-known calcium carbonate-calcium bicarbonate equilibrium accelerated by the scheduled change in carbon dioxide pressure can be. It can be through theoretical knowledge and

Practical experience confirms that the formation and degradation of the water stone is the result of a reversible chemical process, namely:

Ca (HCG ₃ ) ₂ CaCO ₃ + CO ₂ '+ H ₂ :

The upper arrow shows the formation of the water scale, the lower one its degradation, since the calcium carbonate is difficult and the bicarbonate is easily soluble. Calcium compounds are listed in the reaction, since in the formation of scale the excretion of calcium carbonate is decisive, even in the presence of magnesium ions. From the reaction scheme it can be seen that the increase in the partial pressure of the carbon dioxide - in the presence of water - favored the breakdown, but its reduction favored the formation of the scale in practice. Often experienced, variable scale formation and scale breakdown in the same object: can be explained by the fluctuation of the carbon dioxide pressure at the same temperature, while the increase in temperature with the same water quality brings about the splitting off of carbon dioxide. Therefore, water scale is always deposited first on the heat-transferring surface.

The change in the partial pressure of the carbon dioxide comes into play in nature, among other things, in the formation of the stalactite. With the greater pressure in the inner cracks and pores of the zinc stone and dolomite layers, the carbon dioxide-rich water brings the qalium compounds, mainly the limestone, into solution, then the calcium carbonate solution seeps onto the surface of the rock, where there is _; the pressure reduction separates the carbon dioxide - meanwhile - also evaporates water - and itself

- '6 - ■.; ■■

accordingly limestone in the form of stalactite ruled out. -;

When working out the invention

The method and the device for this was one of the most important. Tasks, in addition to eliminating the disadvantages of acid treatment, in that the drop formation ■ accelerated and thereby the process for. a technical solution can be made suitable. Accordingly, the purpose of the invention is to devise a method for removing scale deposits which can be easily carried out, using carbon dioxide of variable pressure under such pressure limits, which is indicated by the specifications of the device taking into account safety ~; Regulations is allowed.

3-2 In one of the advantageous embodiments of the invention, the closed or closable object containing water stone is barked with water. . . Filled with less hardness, then carbon dioxide either from an external source or through partial solution of the water stone in one of mineral acids different -. "■; different acid introduced, whereby the pressure of the gas" is maintained for a constant time (reaction time) . Thereafter, the path for that is "s under a loading.." ■ opened stimmtem pressurized water to a lower-pressure space, whereafter aas water in the room _with:; lower pressure (e.g. room pressure). The water is then kept between the two spaces for a while - advantageously in a turbulent flow - while the carbon dioxide supply is stopped; so the pressure of the dissolved carbon dioxide in the water flowing between the two spaces becomes practically the same everywhere.

After the flow has ^{ceased, the object containing the '-:} scale coating is closed and:; the pressure of the carbon dioxide present there on the '■ - *

. maintained in the previous response time Level increased, after which the procedure continued accordingly will. The method steps described are repeated periodically; pass all cycles from two periods (these do not necessarily have the same duration): from the reaction time and the flow time (flushing time).

. During the reaction time, the carbonate-bio-carbonate equilibrium is shifted in the direction of the bio-carbonate in accordance with the effect of the increased gas pressure. Since the gas pressure is maintained during the reaction time, even after the pressure has been reached, the gas flows into the object (e.g. from a gas cylinder) at the rate determined by the reaction of the dissolution of the scale ₀ In the flow period (flushing period), mainly in its initial phase, carbon dioxide is released from the Liquid keif removed as a result of the rapid reduction in pressure and the equilibrium is shifted in the direction of carbonate formation, after which the carbonate (doh or mud.

The turbulent flow is advantageous because this makes the precipitation much more effective the object in the room, which is always kept under low pressure, e.g. in a vessel or container can be. Carrying back the never-ending blow from the container into the object is through a filter, which is between the container and the circulation pump is switched on, prevents. In the way described, the water stone becomes in the strict sense of the word from the object into a - advantageously emptied - container, but not in

Form of a polluting, acidic solution, but rather as one that is harmless to the environment and can therefore be periodically emptied from the container and anywhere Sludge that can be introduced directly into the ground. Since no mineral acid is used during the procedure this method can also be used for objects in the food industry without special precautionary measures can be used, and the removal of the scale does not cause any additional corrosion damage in the object.

Reduce the operations described the water stone not only chemically but also mechanically, because of the turbulent flow of water the particles loosened during the chemical reaction but not yet reacted are carried away and also bring this into the container. This also applies to those embedded in the water stone Accompanying components, 2.3. those as corrosion by-products resulting hematite particles, siderite and silicate compounds. All of these impurities are during the operation removed from the object provided with water stone and enriched in the container, but no more than a coherent, compact one Coating, rather than an easily removable one at any time Mud.

If the instructions in the device allow, the carbon dioxide released during the flushing period can be absorbed, and the splitting off of the carbon dioxide can also be promoted by placing the entire system under vacuum, and the carbon dioxide thus regenerated can be compressed and fed back into the cycle. In this case, the carbon dioxide also helps remove the water stone ... _; in a closed cycle like water. If but '; ■ the cost of careful sealing with "■ ^;

BADORiQlNAL

are not the cost of the iKohlendioxidersätzes ratio, released during the re-precipitation of carbonate compounds, carbon dioxide may be omitted and the carbon dioxide required _to remove the 'water stone to be covered by a portable gas bottle. In addition, an advantageous embodiment of the entire device consists in designing it as a portable variant, since in such cases the removal of the water stone can be carried out as a service activity and the device according to the invention can be used continuously and effectively.

The invention is based on the attached ' Drawings wherein an exemplary embodiment is cited. Illustration 1 shows the flow diagram and arrangement of the method, FIG. 2 shows the automatic switching device. .

The object 1, made of soft water stone what is to be removed is what is a structural element, container, substance, its surface, course the object is with Sin and exit with a manual valve 2 (which can also be a constriction at the same time) and. connected to the solenoid valve 3. At the beginning of the reaction period The contact clock 4 detailed in Figure 2 closes the solenoid valve 3 and opens ■ the solenoid valve 12. During operation, valve 2 is always in the open state. There at the beginning the reaction period the pressure in the buffer tank 6 is pretty low, the one in the previous one works Cycle switched on circulation pump 5 until the pressure reached in the system the pressure level set by the pressure regulator 7, which of course is higher than is the pressure in the carbon dioxide d-reductors 14. the Circulation pump 5 feeds water from the sludge collecting

BAD ORlQHMAL

Container 9 through the filter 10 and the check valve 11 in the buffer container 6 and the object 1. Through Opening of the solenoid valve 12 is the path of the gas stored in the gas bottle 13 through the reductors 14 and check valve 15 open. The gas. Comes into the buffer container 6 and into the object 1. The gradual increase in the pressure in the buffer container can be read on the manometer 8, the gas flows into the object 1 even after the Pressure, which is determined by the pressure regulator 7, in the rhythm of the chemical reaction.

The reaction (d _o h., The solution of water stone) takes up Erreichung'der the Kontaktuhr 4 set time (for example, "5 minutes), At this time, the Kontaktuhr opens the solenoid valve 3 and closes the solenoid valve 12. Accordingly, rotates, the in Buffer container 6 set pressure, the liquid .from the object 1 suddenly back into the container 9 ', whereby the pressure in the buffer container 6 on the through the. Pressure regulator 7 set level (e.g.

to room pressure) is reduced. At this time, the regulator 7 switches the motor of the pump 5 and so the Liquid between the object 1 imd the schalmns-collecting Container 9 circulates until the side set on the Kor clock 4 (e.g. 30 seconds), whereby the hardness of the water in the object is reduced to the level of the water in the container 9. This closes after the flow-flush period Solenoid valve 3 and the solenoid valve 12 opens, whereby the cycle described is repeated.

During the flushing period, the water that enters the container 9 and carries the water scale embedded in it but through the opening of the water stone escaping accompanying components, e.g. corrosion products, items to be washed from object 1

IAD ORIGiNAL

on the one hand in chemically bound form g on the other hand as floating impurities.

Me Decomposition of Ca (HCOn) ₂ S ie the new formation of calcium carbonate (sludge) is favored by the sudden pressure drop, the pressure drop is accelerated by the dispersion of the water. The deflection plate 16 serves for this purpose, which also the sludge of the accumulating on the lower part of the sludge-collecting container 9

IC prevents sludge and items to be washed. Protection of the Pump 5 and the load on the filter 10 is through the built-in pipe 17 secured, after which the water from the zone above the sludge level in the. Liquid circuit is left. The carbon dioxide that is split off in the sludge collecting container 9 is removed by the drip catcher 13., thereby becomes also the water trickled back into the container while the periodic lowering of the sludge is realized by the drain valve 19.

The duration and the ratio of the reaction and flushing periods are determined taking into account the Volume of the object from which the waterstone is to be removed, the time ratio selected from 5 minutes - half a minute, which was given in the example, is justified if the volume of the object is relatively small (e.g. a pipe section, tubular heat exchanger with not large diameter). In this case, namely, the hardness of the water in the object increases rapidly in the

3C response period, and accordingly decreases the speed of the opening of the water stone. But if the volume of the object is large (e.g.. Steam generator boiler, industrial distiller), the reaction period can also be one or two hours be. In such cases, however, the irrigation

pericde longer, about also the one-time cycle the total amount of water consumed for a long time.

The maximum gas pressure can - if the structure of the object allows it - advantageous 10 to 15 bar, the minimum gas pressure being the room pressure. The temperature of the material used for the operation Water is advantageously the same as the temperature of the environment, so the water should not be heated, because the hydrocarbon solubility associated with the same pressure decreased with increasing temperature. This is' independent of the extent and the pressure resistance of the object is valid, while the pressure conditions and the duration of the reaction and flushing periods can be determined by the information provided by the property.

The sludge-collecting container 9 or at least one side thereof is advantageously made of plexiglass made, in this pail is the extent of the Formation of snakes (water stone effect) also with inspection certificate easy to follow and the time of the conclusion can be selected with certainty. Removal of a stone from the object ksrja on several ways, advantageous due to the cessation of the Sludge formation in the tub 9 can be observed.

The parameters of the process shown as an example in Figures 1 and 2 and of the device changes the details of the concrete Objekxs mutatis mutandis ", so Z.3 _o the reaction time is increased when the degree besop_ders increased, the volume of the object, but it is in this case it is also possible that the scale can be removed in one cycle.At the same time, the emptying (flushing) period can be completely omitted for devices with large volumes, e.g. boilers, since the achievable

Water speed does not affect the discharge of the silt enables. Instead, this task can be accomplished by a separate operation, advantageously by application of a rinse water "

"The advantages of the method described can thus be summarized in that the Water stone from the object containing the water stone be removed periodically in a non-operational state can, whose frequency is chosen so that the amount (the thickness) of the water stone under one still tolerable threshold remain at the distance the water stone eliminates the use of harmful acids that damage the device and so will the environment through the landfilling of the Waste of removal of the water stone not damaged. ·

Claims (1)

■ "42 611 m / fg ^ 3328 KERIPAR, Budapest / Hungary METHOD AND DEVICE FOR REMOVING HYDROSTONE COATINGS WITHOUT ACID TREATMENT Claims , • 1. Procedure for removing scale without treatment with a mineral acid, characterized in that the water stone is "mixed under pressure" with carbon dioxide, preferably with water, and the water is passed from the object containing the water stone into a separate room while reducing the pressure, Here the sludge separating from the water separates from the water, then brings the water stone back into contact with water, under pressure again -1? "saturates with cone dioxide and the enumerated ope- " \ rations repeated continuously, i .2. Method according to Claim 1, characterized in that the food is served of carbon dioxide into the water is repeated temporarily adjusts and during the 'duration of the adjustment allows the water to flow between the object containing the water stone and the separated space. '3 ° method according to spoke 1, characterized in that one in the Water is only a containing object, - repeats water ", feeds and from it the water removed / and the hardness of the fed water always lower than the hardness of the of distant water. 4. Decay according to Claim 1, characterized in that the partial pressure of the carbon dioxide in the water used to open the water stone is changed periodically. _:: 5. The method according to any one of claims 1 to 4, thereby ge k e -η η ζ e i c trn e t that one out of the water, wcn / ues out of the the water stone containing object was separated, the sludge the floating impurities, the Sutileut .a.urr; h Separation and / or filtration withdraws, then the water in the object again with the water stone in Brings contact. 6. Device for performing the method according to one of claims 1 to 5 _}, characterized in that 'the object containing the water scale (1) is connected to a device which periodically feeds the carbon dioxide at a regulated pressure. 7. Apparatus _for carrying out the method according to any one of claims 1 to 5, characterized in that check valves to prevent the flow of water su the carbon dioxide source, and the carbon dioxide in the direction opposite to the flow of the water exiting from the object. Water are provided. 8. Device according to claims 6 or 7 » characterized in that in the -Weg of the carbon dioxide and water valves, which their Periodically regulate the flow, are switched on. 9. Device according to one of claims 6 to 8, characterized in that the penetration of the sludge carried out by the water from the object containing the water stone was, in the recirculating water branch through-i a pass-through and / or a filter that is switched on in the path of the water is prevented. 1O ₀ device for carrying out the method according to claim 2, characterized in that a pressure sensor is used as a signal source to control the pump regulating the flow of water.