WO2005115927A1

WO2005115927A1 - Device for reduction of scale formation

Info

Publication number: WO2005115927A1
Application number: PCT/RU2005/000006
Authority: WO
Inventors: Aleksandr Michailovich Fridkin; Nicolai Romanovich Grebenchikov; Valerij Mansurovich Safin; Stanislav Michailovich Kochergin
Original assignee: Obschestvo S Ogranichennoi Otvetstvennostiu 'akvatoria' (The Ooo 'akvatoria')
Priority date: 2004-05-26
Filing date: 2005-01-13
Publication date: 2005-12-08
Also published as: RU2261843C1

Abstract

The present invention relates to water treatment and can be used for prevention of scale formation on heating surfaces of heat-exchange apparatus, steam and hot-water boilers, for desalination and evaporation of water, in production processes including evaporation of aqueous solutions, in agriculture, in husehold, in sanatoria and health resorts etc. The technical result is achieved owing to that in the device for reduction of scale formation including housing, means for water feed, means for water treatment by quasi-softening and means for outlet of treated water means for water treatment is made out of an ion-exchange material of space-globular structure (SGS).

Description

DEVICE FOR REDUCTION OF SCALE FORMATION

TECHNICAL FIELD The present invention relates to water treatment and can be used for prevention of scale formation on heating surfaces of heat-exchange apparatus, steam and hot-water boilers as well as for desalination and evaporation of water, in production processes including evaporation of aqueous solutions, in agriculture, in household, in sanatoria and health resorts etc. PRIOR ART Devices are known based on various principles of operation and destined for reduction of scale formation by means of water softening. Thus, according to "Water Supply" by N.N.Abramov, Stroyizdat publishers, Moscow, 1982, p. 300, in order to reduce scale formation hard water containing ions of Ca and Mg is softened by reagent method. Water is being passed through a chemical reagent fixing ions of Ca and Mg into not readily soluble compounds calcium carbonate and magnesium hydroxide which can be easily removed by precipitation and filtering. In devices containing thermo-softener (as described in Patent RU No.2152905 of 01.02.1996, C02 F 1/20, C02 F 5/02) decrease in scale formation is also achieved by reagent softening with use of lime and soda at a temperature above 100°C. Additional heating allows to accelerate removal of hardness ions. Membrane apparatus are known (see the above mentioned book, p. 301) where incoming hard water flows in the chamber on one side of the cation exchanger membrane while NaCl brine flows on the other side of the membrane. Sodium ions migrate into the membrane and further into the hard water while calcium ions migrate in opposite direction, i.e from hard water into brine. The known devices are also destined for reduction of scale formation owing to softening water. Hard water is treated by a practically similar method in devices known from the Patents EP 0056850 of 28.01.1982, Int.Cl. C02F 1/42, RU 2163568 of 30.11.1999, IntCl. C02F 1/42 etc. In 1936 a technical procedure was discovered which allows in many cases to prevent scale formation on the surface without necessary purification of water from hardness salts and degassing. The phenomenon was named magnetohydrodynamic (MHD) resonance, or quasi-softening of water, and obtained its theoretical basis in the eighties last century. According to this model, physical essence of MHD resonance consists in structural rearrangement of liquid initiated by resonance frequency of Lorentz force. Out of water with modified structure calcium carbonate is crystallized in the form of aragonite. Crystallographic discrepancy of crystals Fe₂O₃/aragonite is 0.121, siderite/aragonite - 0.191. It means that scale will be formed on the heat-exchange surface at supersaruration values 3.5 - 4.5 times greater than usually for similar conditions. Besides, aragonite has a little bit higher solubility, lower adhesion to steel and cohesion between crystals. Hence, aragonite, even being crystallized on the surface, will be carried away by the liquid flow in the form of individual crystals. Said conceptions conform with practical results very well. Besides, it was repeatedly demonstrated that water undergone structural rearrangement in the MHD resonator is capable to wash off the scale deposited before. It is explained with that crystallization of calcium carbonate out of such water occurs in the form of aragonite. Crystallographic discrepancy of calcite and aragonite is 0.14, i.e. aragonite grows on the surface of calcite. Simultaneously recrystallization of calcite into aragonite takes place. As a result of lower adhesion of aragonite to metal surfaces and low cohesion of aragonite crystals to each other the scale formed before becomes loose, separates from the surface and is carried away with water flow. (V.A.Prisyazhniuk. Physicochemical Fundamentals of Prevention Crystallization on Heat-exchange Surfaces. SantechnikaNo.lO, 2003, p. 30). Devices are known from the state of the art which make it possible to reduce scale formation on the basis of the principle described above. Thus, devices for magnetic water treatment (described, for instance, in Patent RU 2118614 of 05.03.1997, C02 F 1/18) make it possible to reduce scale formation owing to quasi-softening of water. In such devices hard water is being passed through means for quasi-softening, namely a component (magnetron) comprising permanent magnet or electromagnet where 20 to 30 per cent of all the liquid are being subjected to magnetic treatment in magnetic field variable in time and gradient over space. Said magnetic treatment allows to obtain water giving no sediments at boiling. Patent for the known device protects optimum mode of quasi-softening as well (only a portion of water is subjected to magnetic treatment, not the whole volume). In most other devices of similar kind whole passing water is treated by means of magnetic field. The known device is most close to the claimed device by its technical essence because both of the devices provide reduction of scale formation owing to the quasi-softening effect. The known device disclosed in Patent RU 2118614 of 05.03.1997, C02 F 1/18 is chosen by us as a prototype.

DISCLOSURE It is an object of the present invention to create a device allowing substantially reduce scale formation at boiling water as well as cut down labour consumption at manufacturing of the device and simplify operation of the latter. The technical result is achieved owing to that in the device for reduction of scale formation including housing, means for water feed, means for water treatment by quasi-softening and means for outlet of treated water means for water treatment is made out of an ion-exchange material of space-globular structure (SGS). It should be noticed that the SGS material is globular three-dimensional ionite with globules size 5 to 7 μm. Microglobules in SGS ionite form regular high- permeable structure which is caused by spontaneous self-regulating mechanism of polymer formation. Average pore size is 1 to 3 μm, total porosity more than 65% vol. This material is usually employed for sorption processes at high flow rate of passing solutions. Owing to that microglobules size of SGS ionite is by two orders of magnitude less than in standard-grain ionite (5 - 7 μm against 0.5 - 0.7 μm) volumetric flow rates of passing solutions can amount to values 100 and more times greater than volumetric flow rates of solutions being passed through stationary layer of ionite with usual grain size (1000 - 2000 against 10 - 15 spec.vol./hour). Structure and properties of SGS ionite are known from e.g. Encyclopaedia of Polymers, Sovetskaya Encyclopaedia publishers, 1972, p. 652. Various versions of method for obtaining a SGS material, e.g. in accordance with USSR Author's Certificates 1378319 of 23.05.1985, CO8 J5/20, CO8 G8/22 or 1023788 of 24.10.1980, C08 J 9/10, make it possible to extend considerably range of size of its pores and, consequently, to increase its permeability when used as a sorbent. Experimental investigations fulfilled by the inventors proved that interaction of water with a SGS material results in physicochemical changes in its structure resembling condition of water after magnetic treatment. Similarity of said processes is indicated by absence of sediment on the surfaces of heating apparatus during long period of operation and formation of easily removable aragonite after prolonged boiling of water. In both processes quantity of hardness salts does not decrease, i.e. there is quasi-softening of hard water that takes place. It should be noticed that at the time of writing the new phenomenon discovered by the inventors is being comprehensively studied with participation of experts in various branches of science and technology in order to explain mechanism of interaction of hard water with SGS material. In preferable embodiment of the claimed device means for water treatment is made in the form of hollow cylinder manufactured of SGS polymer with size of pores 0.01 to 3 μm. Matrix structure of the polymer corresponds to the following formula:

OH The housing of the device is made in the form of a cylinder too.

Dimensions ratios for the cylinder of SGS material are as follows: ratio external diameter to internal diameter is 1.7 - 1.9, ratio external diameter to height is 0.2 - 0.3. SPECIFICATION DRAWINGS The invention is elucidated with the accompanying drawing in which sectional view of the device is presented where 1 - hollow cylindrical housing made of steel or plastic or any other proper material, 2 - means for treatment of water by quasi-softening of the latter made in the form of hollow cylinder of SGS material mounted in housing 1 coaxially forming a gap in which water is being supplied by means for water feed (e.g. by pump) - not shown in the Figure. Out of the device water is being evacuated by means for outlet of treated water — not shown in the Figure. Cylinder 2 is choked with cap 3. 4 is the lid of the device. PREFERRED EMBODIMENT The claimed device operates as follows. Water containing hardness salts is directed by means for feed into annular gap between housing 1 of the device and hollow cylinder 2. From the gap water passes through pores of SGS material into internal cavity of cylinder 2. Flow rate of passing water for maximum efficiency is usually selected empirically. For instance, for a device having cylinder 2 with the following dimensions: height 245 - 247 mm, external diameter 73 - 75 mm, internal diameter 40 - 42 mm optimum flow rate is at least 5 1/min. Treated water is evacuated by means for outlet of treated water into storage tank or directly to user. During first 30 - 60 min usual filtration through ionite is being observed accompanied with some reduction of hardness salts content (by 10 - 15%), afterwards hardness salts content remains constant during water treatment process but scale at boiling such water does not form. First after some 100 - 200 hours of operation (depending on hardness salts concentration) formation of loose white sediment (aragonite) is observed which can be readily removed from the surface of the heater. At realization of the claimed device internal cylinder 2 was manufactured of inert porous material - SGS polymer with pores size 0.01 - 3 μm. Housing of the device was put into a casing made of polypropylene. The following example will serve to further elucidate the manner in which the present invention is practiced. The device manufactured according to the present invention was used for treatment of water containing CaCl₂ ^' 6H O and MgCl₂ ^' 6H₂0. Water was passed through the device at flow rate 5 1/min. Parameters of original water and information about scale formation at boiling treated water are given in the Table.

Table

The data presented indicate that at boiling water treated in the claimed device scale is formed after prolonged boiling. In running_rwater heaters loose sediment in the form of light film is being risen on the surface by water flow and can be easily removed as a scum. When boiling non-running water the light film rises on the surface of water. Results of X-ray diffraction analysis indicate that the sediment constitutes aragonite. Water was analyzed in accordance with the following standards: GOST 2874-82 Potable water. Hygienic requirements and quality control. GOST 3351-74 Potable water. Methods for determination of taste, smell, colority and turbidity. GOST 4011-72 Potable water. Methods for measurement of mass concentration of total iron. GOST 4974-72 Potable water. Methods for determination manganese content.

Claims

1. Device for reduction of scale formation including housing, means for water feed, means for treatment of water by quasi-softening and means for outlet of treated water characterized in that means for water treatment is made of a material with space-globular structure (SGS).

2. Device according to Claim 1 characterized in that means for water treatment is made of a SGS material with size of pores 0.01 - 3 μm while water is being passed through said device at flow rate at least 5 1/min.

3. Device according to Claim 2 characterized in that means for water treatment is made in the form of a hollow cylinder mounted coaxially in the housing of the device.

4. Device according to Claim 3 characterized in that ratio of external diameter of the hollow cylinder to its internal diameter is 1.7 - 1.9, ratio of external diameter to height is 0.2 - 0.3.