RU2108978C1 - Method and device for preventing biofouling of equipment of water systems - Google Patents

Abstract

FIELD: biofouling protection. SUBSTANCE: invention relates to heat exchangers, pipes, and other equipment with surfaces contacting with water in chemical, petrochemical, pharmaceutical, food, textile, power, and other industries. Invention consists in providing adhesion of biofouling microorganisms to a fibrous attachment. On the same attachment, predatory aquatic life is later placed to eat biofouling microorganisms and each other so providing trophic circuit. Device also contains units for water intake and take off, air intake and withdrawal of liquid. EFFECT: facilitated biofouling protection. 1 dwg, 2 tbl

Description

 The invention relates to methods for preventing biofouling of water systems and can be used to combat biological fouling of heat exchangers, pipes and other surfaces that are washed with water in chemical, petrochemical, pharmaceutical, food, textile and other industries and energy.

 Due to the widespread use in technology, in particular during heat transfer, of closed water circulating systems, the threat of biological fouling of heat exchangers, pipes and other equipment through which water flows sharply increases.

 Chemical methods of controlling biological fouling of heat exchangers and other technological equipment are widely used all over the world. These methods are based on the use of various chemicals that inhibit the vital activity of fouling microorganisms, or kill them by oxidation (chlorine, bromine, hydrogen peroxide), rupture of the cell wall or membrane (surface-active substances), toxic effects on microbial cells (synthetic biocides ) etc.

 The disadvantages of these methods is that they require the constant introduction of oxidizing agents, solubilizing or poisonous substances into the water, which are not only environmentally unsafe, but also pose a certain threat to the health of the people who service the water circulation systems of enterprises.

 There is a non-reagent method for preventing biofouling of technological equipment, which is based on the use of a fiber nozzle made in the form of a ruff in water circulating systems, to the surface of which adhesion of the cells of fouling microorganisms occurs, resulting in a decrease in the speed and mass of fouling in the apparatus [1]. This method, which serves as an analogue of the inventive invention, certainly has an advantage over chemical methods, since it does not require the introduction of any substances into the water that dissolve in it, and thus eliminates water pollution by these substances.

 The disadvantages of the analogue are that the fiber nozzle used in it is made in the form of ruffs that have a volumetric structure in water, and as a result of the adhesion of microorganisms to the villi, they are quickly transformed into mucous cylinders, in the middle of which anaerobic zones form, where rotting and decomposition of microbial cells takes place . As a result of ongoing anaerobic processes, foul-smelling and corrosive substances, such as mercaptans, hydrogen sulfide, and others, which degrade water quality, impede the operation of water circulation systems, and contribute to corrosion of equipment, are released into the water. In addition, the technological features of the brushes allow you to place them in the apparatus for combating biofouling only vertically, which leads to the lowering and clumping of their villi, which in their mass become inaccessible for settling fouling microorganisms on them; the process of brush regeneration is also becoming more complicated - the breakdown of biomass that has stuck to them.

 Closest to the totality of features to the proposed invention is the "Method of preventing biofouling in water recycling systems" [2], which is a prototype. This method involves passing water through a fiber nozzle made in the form of brushes made from a mixture of hydrophilic (glass or basalt) and hydrophobic (nylon or polyethylene) fibers in a certain ratio.

 The disadvantages of the prototype is, firstly, the fact that in the volumetric nozzle rotting of the biomass occurs, and the removal of the latter during regeneration is difficult. In addition, hydrophilic and hydrophobic fibers are designed to attract various bacteria to their surface and adhere (adhesion) to it, which form fouling of technological equipment, which is very important and useful, but not enough, since it leads to quick siltation of the nozzle and requires frequent regeneration of it , which complicates and complicates the operation.

 These disadvantages of the prototype are eliminated in the proposed method using a nozzle type "Wii".

 The solution to the problem of biofouling fouling heat exchangers and other technological equipment according to the invention is achieved due to the fact that, firstly, the device for combating biofouling is equipped with a fiber nozzle made in the form of flat rather than voluminous brushes, strong and technological formations - nozzle type "Wii " Secondly, a flat nozzle of the type "Viya" is placed (located) horizontally in the device, which makes the surface of each fiber available for settlement of biofouling on it, and facilitates the regeneration of the nozzle. Thirdly, - this is the most important - the proposed method provides for the settlement in the device for combating biofouling (namely, the nozzle "Viya") of hydrobionts-predators of various trophic levels, which eat fouling microorganisms and each other and thus carry out constant natural biological regeneration nozzles, increasing the time of continuous operation of the device.

 The drawing shows a device for preventing biofouling.

 The device consists of a tank with a conical bottom 1 with a nozzle of the type “Viya” 2 placed in it, the tank 1 also has units for supplying 3 and for removing 4 water, a bypass 5, an air supply and dispersion unit 6, a pipe for emptying the container 7. A nozzle of the type "Wii" 2 is placed in the tank 1 in horizontal rows that are offset relative to each other to ensure reliable contact of the water that flows through the device with the nozzle. Hydrobionts-predators of the first and second trophic levels (protozoa, crustaceans, mollusks, etc.) are placed on the Viya nozzle.

 The device operates as follows. Water that circulates in a closed cycle of water supply and is used for cooling in heat exchangers, for other technological purposes, enters a tank 1 with a nozzle of the type "Viya" 2 through a water supply unit 3, passes between the fibers of the nozzle 2 and is discharged through a node 4. Upon contact Biofouling of the latter occurs with a fiber nozzle of the type “Viya” 2, and specially introduced hydrobionts-predators, which form chains and networks in the device, feed on the biomass of fouling microorganisms, constantly regulating their number, and eat each other .

 With particularly intensive biofouling, the device requires periodic regeneration, which is carried out as follows: open the valve on the bypass pipe 5 (so as not to stop the main production), close the valves on the supply line 3 and water outlet 4, open the valve on the air supply line 6 and for some time using an air-water mixture shake the biofouling from the nozzle "Viya" 2. Then open the valve on the discharge line 7 and release water from the device with microorganisms-fouling and hydrobionts-predators in analysis. They close the valve on the air supply line 6, close the valve on the discharge line 7 and open the valves on the supply lines 3 and water outlet 4. After filling the tank 1 with water, the bypass 5 is closed. During regeneration from the nozzle, "Viya" 2 is washed out on all hydrobionts-predators, and therefore they do not need to be re-introduced into the device.

 In the table. 1, 2 presents data on the degree of purification of circulating water supplied to the cooling of heat exchangers.

Analysis of the sludge taken from the tower of the tower showed that the content of the organic part (pp, 600 ^o C) decreased by 1.3 times.

The amount of suspended solids in the water discharged into the sewer was 4.0 mg / dm ³ .

 Thus, the use of the proposed method and device can effectively prevent biofouling of technological equipment in water circulation systems.

Sources of information
1. Gvozdyak P.I., Nikonovskaya G.N., Udilova O.F., Globa L.I. The role of the fibrous nozzle in the prevention of biofouling apparatus. // Chemistry and technology of water. 1990, N 5, p. 462-466.

 2. A. p. USSR N 1535842, class. C 02 F 1/50. A way to prevent biofouling in water recycling systems. / P.I. Gvozdyak, G.N. Nikovskaya, L.I. Globa et al. - The Public. 1/15/90, Bull. N 2.

Claims (2)

 1. A method for preventing biofouling of technological equipment in aqueous systems, which includes the adhesion of fouling microorganisms to the fibrous nozzle, characterized in that at least two trophic levels of hydrobiont predators are fed to the fibrous nozzle, which feed on fouling microorganisms and eat each other, forming at this trophic chains and nets.  2. A device for preventing biofouling of technological equipment in water systems, which includes a container with a nozzle located in it, nodes for supplying and discharging water and air, as well as the discharge of liquid, the fibrous nozzle being made in the form of a flat nozzle of the “Viya” type and placed in the device in horizontal rows, while the rows are offset relative to each other.

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